Dennis Whyte: Nuclear Fusion and the Future of Energy

00:00:00.000 | Why weren't we pushing towards economic fusion

00:00:02.320 | and new materials and new methods of heat extraction

00:00:05.400 | and so forth?

00:00:06.240 | Because everybody knew fusion was 40 years away.

00:00:08.640 | And now it's four years away.

00:00:11.020 | - The following is a conversation with Dennis White,

00:00:15.940 | nuclear physicist at MIT and the director

00:00:18.840 | of the MIT Plasma Science and Fusion Center.

00:00:22.280 | This is the Lex Friedman Podcast.

00:00:24.360 | To support it, please check out our sponsors

00:00:26.120 | in the description.

00:00:27.560 | And now, dear friends, here's Dennis White.

00:00:31.200 | Let's start with a big question.

00:00:33.780 | What is nuclear fusion?

00:00:35.320 | - It's the underlying process that powers the universe.

00:00:38.600 | So as the name implies, it fuses together

00:00:41.640 | or brings together two different elements,

00:00:46.120 | technically nuclei, that come together.

00:00:49.100 | And if you can push them together close enough

00:00:51.900 | that you can trigger essentially a reaction,

00:00:55.000 | what happens is that the element typically changes.

00:00:58.960 | So this means that you change from one element

00:01:00.960 | to another, chemical element to another.

00:01:03.160 | Underlying what this means is that you change

00:01:05.200 | the nuclear structure.

00:01:06.600 | This rearrangement through equals MC squared

00:01:09.040 | releases large amounts of energy.

00:01:11.120 | So fusion is the fusing together of lighter elements

00:01:15.320 | into heavier elements.

00:01:17.140 | And when you go through it, you say, oh, look,

00:01:19.440 | so here were the initial elements, typically hydrogen.

00:01:23.080 | And they had a particular mass, rest mass,

00:01:26.440 | which means just the mass with no kinetic energy.

00:01:29.400 | And when you look at the product afterwards,

00:01:31.560 | it has less rest mass.

00:01:33.360 | And so you go, well, how is that possible?

00:01:35.160 | Because you have to keep mass,

00:01:36.600 | but mass and energy are the same thing,

00:01:38.780 | which is what E equals MC squared means.

00:01:41.360 | And the conversion of this comes into kinetic energy,

00:01:45.140 | namely energy that you can use in some way.

00:01:47.840 | And that's what happens in the center of stars.

00:01:51.440 | So fusion is literally the reason life

00:01:54.720 | is viable in the universe.

00:01:57.560 | - So fusion is happening in our sun.

00:02:00.280 | And what are the elements?

00:02:01.720 | - The elements are hydrogen that are coming together.

00:02:05.440 | It goes through a process which is probably,

00:02:07.400 | it's a little bit too detailed,

00:02:09.280 | but it's a somewhat complex catalyzed process

00:02:13.640 | that happens in the center of stars.

00:02:16.440 | But in the end, stars are big balls of hydrogen,

00:02:19.360 | which is the lightest, that's the simplest element,

00:02:21.680 | the lightest element, the most abundant element,

00:02:23.600 | most of the universe is hydrogen.

00:02:25.240 | And it's essentially a sequence through which

00:02:28.480 | these processes occur that you end up with helium.

00:02:31.700 | So those are the primary things.

00:02:33.000 | And the reason for this is because helium

00:02:36.120 | has features as a nucleus,

00:02:38.760 | like the interior part of the atom,

00:02:41.100 | that is extremely stable.

00:02:43.480 | And the reason for this is helium has two protons

00:02:46.500 | and two neutrons.

00:02:47.840 | These are the things that make up nuclei,

00:02:49.240 | that make up all of us, along with electrons.

00:02:51.800 | And because it has two pairs, it's extremely stable.

00:02:56.200 | And for this reason, when you convert the hydrogen

00:03:00.160 | into helium, it just wants to stay helium,

00:03:02.440 | and it wants to release kinetic energy.

00:03:04.820 | So stars are basically conversion engines

00:03:09.080 | of hydrogen into helium.

00:03:11.280 | And this also tells you why you love fusion.

00:03:15.160 | I mean, 'cause our sun will last 10 billion years,

00:03:19.000 | approximately, that's how long the fuel will last.

00:03:22.880 | - But to do that kind of conversion,

00:03:24.400 | you have to have extremely high temperatures.

00:03:26.480 | - It is one of the criteria for doing this.

00:03:28.880 | But it's the easiest one to understand.

00:03:30.680 | Why is this?

00:03:31.520 | It's because effectively what this requires

00:03:35.560 | is that these hydrogen ions,

00:03:39.680 | which is really the bare nucleus,

00:03:41.280 | so they have a positive charge,

00:03:42.720 | everything has a positive charge of those ones,

00:03:45.120 | is that to get them to trigger this reaction,

00:03:47.800 | they must approach within distances

00:03:50.480 | which are like the size of the nucleus itself.

00:03:52.920 | Because the nature, in fact, what it's really using

00:03:55.840 | is something called the strong nuclear force.

00:03:57.800 | There's four fundamental forces in the universe.

00:03:59.960 | This is the strongest one.

00:04:01.760 | But it has a strange property,

00:04:03.240 | is that while it's the strongest force by far,

00:04:06.020 | it only has impact over distances

00:04:08.620 | which are the size of a nucleus.

00:04:10.360 | So to get, let's put that into, what does that mean?

00:04:13.180 | It's a millionth of a billionth of a meter.

00:04:17.040 | Okay, incredibly small distances.

00:04:19.760 | But because the distances are small

00:04:21.800 | and the particles have charge,

00:04:23.560 | they want to push strongly apart.

00:04:25.640 | Namely, they have repulsion that wants to push them apart.

00:04:28.560 | So it turns out when you go through the math of this,

00:04:31.160 | the average velocity or energy of the particles

00:04:34.480 | must be very high to have any significant probability

00:04:38.500 | of the reactions happening.

00:04:40.240 | And so the center of our sun

00:04:42.000 | is at about 20 million degrees Celsius.

00:04:45.920 | And on Earth, this means it's one of the first things

00:04:48.360 | we teach entering graduate students.

00:04:50.600 | You can do a quick, basically power balance

00:04:54.600 | and you can determine that on Earth

00:04:56.600 | it requires a minimum temperature

00:04:58.760 | of about 50 million degrees Celsius on Earth.

00:05:02.200 | - To perform fusion.

00:05:03.660 | - To get enough fusion that you would be able to make,

00:05:08.420 | get energy gain out of it.

00:05:10.840 | So you can trigger fusion reactions at lower energy,

00:05:13.360 | but they become almost vanishingly small

00:05:15.920 | at lower temperatures than that.

00:05:18.200 | - First of all, let me just link around some crazy ideas.

00:05:20.320 | So one, the strong force,

00:05:22.920 | just stepping out and looking at all the physics.

00:05:26.360 | Is it weird to you that there's these forces

00:05:29.120 | and they're very particular,

00:05:30.840 | like it operates at a very small distance

00:05:32.520 | and then gravity operates at a very large distance

00:05:34.880 | and they're all very specific

00:05:37.280 | and the standard model describes

00:05:39.800 | three of those forces extremely well and there's--

00:05:42.000 | - And this is one of them.

00:05:43.400 | - Yeah, this is one of them.

00:05:44.240 | And it's just all kind of works out.

00:05:46.720 | There's a big part of you that's an engineer.

00:05:51.400 | Did you step back and almost look

00:05:52.880 | at the philosophy of physics?

00:05:54.920 | - So it's interesting 'cause as a scientist,

00:05:57.160 | I see the universe through that lens of essentially

00:06:00.320 | the interesting things that we do are through the forces

00:06:02.640 | that get used around those.

00:06:04.880 | And everything works because of that.

00:06:07.660 | Richard Feynman had, I don't know if you ever read

00:06:09.920 | Richard Feynman, it's a little bit of a tangent,

00:06:11.800 | but-- - He's never been

00:06:12.680 | on the podcast. - He's never been

00:06:13.600 | on the podcast.

00:06:14.440 | He was unfortunately passed away,

00:06:15.760 | but like a hero to almost all physicists.

00:06:19.320 | And a part of it was because of what you said.

00:06:21.840 | He kind of looked through a different lens

00:06:24.000 | at these, what typically look like very dry equations

00:06:28.520 | and relationships and he kind of,

00:06:30.560 | I think he brought out the wonder of it in some sense,

00:06:32.880 | right, for those.

00:06:34.520 | He posited what would be, if you could write down

00:06:36.880 | a single, not even really a sentence,

00:06:39.480 | but a single concept that was the most important thing

00:06:43.280 | scientifically that we knew about.

00:06:45.520 | That in other words, you had only one thing

00:06:47.480 | that you could transmit like a future or past generation.

00:06:51.480 | It was very interesting.

00:06:53.120 | So it's not what you think.

00:06:54.240 | It wasn't like, oh, strong nuclear force

00:06:56.300 | or fusion or something like this.

00:06:58.480 | And it's very profound, which was that the reason

00:07:02.520 | that matter operates the way that it does

00:07:05.920 | is because all matter is made up of individual particles

00:07:10.440 | that interact each other through forces.

00:07:12.920 | That was it.

00:07:13.760 | So just...

00:07:14.600 | Atomic theory basically.

00:07:15.600 | Yeah.

00:07:16.880 | Which is like, wow, that's like so simple,

00:07:19.480 | but it's not so simple.

00:07:20.860 | It's because like, who thinks about atoms

00:07:23.560 | that they're made out of?

00:07:24.860 | This is a good question I give to my students.

00:07:27.860 | How many atoms are in your body?

00:07:29.300 | Like almost no students can answer this,

00:07:31.040 | but to me, that's like a fundamental thing.

00:07:33.000 | By the way, it's about 10 to the 28.

00:07:35.040 | 10 to the 28.

00:07:36.360 | So that's a trillion, million, trillion, trillion,

00:07:40.720 | or something like that, yes.

00:07:41.560 | So one thing is to think about the number

00:07:43.360 | and the other is to start to really ponder the fact.

00:07:46.520 | That it all holds together.

00:07:47.600 | Yeah, it all holds together and you're actually that.

00:07:49.800 | You're more that than you are anything else.

00:07:51.840 | Yes, exactly, yeah.

00:07:53.400 | No, I mean, there are people who do study such things

00:07:56.480 | of the fact that if you look at the, for example,

00:07:59.600 | the ratios between those fundamental forces,

00:08:02.560 | people have figured out, oh, if this ratio

00:08:04.400 | was different by some factor, like a factor of two

00:08:06.880 | or something, I was like, oh, this would all not work.

00:08:10.040 | And you look at the sun, right?

00:08:12.120 | So it turns out that there are key reactions

00:08:15.440 | that if they had slightly lower probability,

00:08:17.560 | no star would ever ignite.

00:08:19.200 | And then life wouldn't be possible.

00:08:21.880 | It does seem like the universe set things up for us

00:08:26.280 | that it's possible to do some cool things,

00:08:29.140 | but it's challenging.

00:08:30.680 | So that it keeps it fun for us.

00:08:32.980 | Yeah, yeah, that's the way I look at it.

00:08:34.480 | I mean, the multiverse model is an interesting one

00:08:38.360 | because there are quantum scientists who look at it

00:08:40.800 | and figure, it's like, oh, it's like, oh yeah.

00:08:42.880 | Like quantum science perhaps tells us

00:08:44.600 | that there are almost an infinite variety

00:08:46.760 | of other universes, but the way that it works probably

00:08:50.880 | is it's almost like a form of natural selection.

00:08:53.080 | It's like, well, the universes that didn't have

00:08:55.640 | the correct or interesting relationships

00:08:58.280 | between these forces, nothing happens in them.

00:09:00.980 | So almost by definition, the fact that we're having

00:09:02.960 | this conversation means that we're in one

00:09:05.200 | of the interesting ones by default.

00:09:07.600 | - Yeah, one of the somewhat interesting,

00:09:09.080 | but there's probably super interesting ones

00:09:11.880 | where I tend to think of humans as incredible creatures.

00:09:15.920 | Our brain is an incredible computing device,

00:09:18.560 | but I think we're also extremely cognitively limited.

00:09:23.000 | I can imagine alien civilizations that are much, much,

00:09:26.320 | much, much more intelligent in ways we can't even comprehend

00:09:30.180 | in terms of their ability to construct models of the world,

00:09:34.260 | to do physics, to do physics and mathematics.

00:09:36.920 | - I would see it in a slightly different way.

00:09:39.260 | It's actually, it's because we have creatures

00:09:44.260 | that live with us on the Earth that have cognition,

00:09:47.220 | that understand and move through their environment,

00:09:49.780 | but they actually see things in a way,

00:09:53.060 | or they sense things in a way

00:09:54.540 | which is so fundamentally different, it's really hard.

00:09:59.060 | It's the problem is the translation,

00:10:00.660 | not necessarily intelligence.

00:10:02.020 | So it's the perception of the world.

00:10:03.460 | So I have a dog, and when I go and I see my dog

00:10:07.060 | like smelling things, there's a realization that I have

00:10:10.340 | that he sees or senses the world in a way that I can never,

00:10:14.820 | like I can't understand it because I can't translate

00:10:17.540 | my way to this.

00:10:18.560 | We get little glimpses of this as humans though,

00:10:20.780 | by the way, because there are some parts of it,

00:10:22.980 | for example, optical information, which comes from light,

00:10:26.880 | is that now because we've developed the technology,

00:10:29.480 | we can actually see things.

00:10:31.240 | I get this as one of my areas of research is spectroscopy.

00:10:36.820 | So this means the study of light.

00:10:39.020 | And I get this quote unquote, see things

00:10:40.700 | or representations of them from the far infrared

00:10:44.020 | all the way to like hard, hard x-rays,

00:10:46.460 | which is several orders of magnitude

00:10:48.740 | of the light intensity, but our own human eyes,

00:10:52.280 | like see a teeny, teeny little sliver of this.

00:10:55.520 | So that even like bees, for example,

00:10:57.300 | see a different place than we do.

00:10:59.380 | So I don't, I think if you think of,

00:11:02.460 | there's already other intelligences like around us

00:11:06.020 | in a way, in a limited way,

00:11:08.860 | because of the way they can communicate.

00:11:10.320 | But it's like, those are already baffling in many ways, yeah.

00:11:14.540 | - If we just focus in on the senses,

00:11:16.200 | there's already a lot of diversity,

00:11:18.300 | but there's probably things we're not even considering

00:11:20.740 | as possibilities.

00:11:22.020 | For example, whatever the heck consciousness is,

00:11:25.740 | could actually be a door into understanding

00:11:30.240 | some physical phenomena we haven't even begun understanding.

00:11:33.540 | So just like you said, spectroscopy,

00:11:35.560 | there could be a similar kind of spectrum

00:11:37.120 | for consciousness that we're just like,

00:11:39.200 | we're like these dumb descendants of apes

00:11:42.720 | like walking around.

00:11:43.620 | It sure feels like something to experience the color red.

00:11:46.740 | But like we don't have, it's the same as in the ancient times

00:11:50.240 | you experienced physics.

00:11:51.240 | We experienced light.

00:11:52.440 | It's like, oh, it's bright.

00:11:53.520 | And you know, and you construct kind of

00:11:56.120 | semi-religious kind of explanations.

00:11:58.720 | - We might actually experience this faster than we thought

00:12:01.080 | 'cause we might be building another kind of intelligence.

00:12:05.040 | - Yeah, and that intelligence will explain to us

00:12:08.520 | how silly we are.

00:12:10.080 | - There was an email thread going around the professors

00:12:12.760 | in my department already of,

00:12:14.880 | so what is it going to look like to figure out

00:12:17.080 | if students have actually written their term papers

00:12:19.840 | or it's chat--

00:12:21.720 | - ChatGPT.

00:12:22.560 | - ChatGPT.

00:12:23.380 | It was, so as usual, we tend to be empiricists

00:12:29.960 | in my field, so of course they were in there

00:12:32.160 | like trying to figure out if it could answer like questions

00:12:35.760 | for a qualifying exam to get into the PhD program at MIT.

00:12:38.760 | They didn't do that well at that point,

00:12:42.800 | but of course this is just the beginning of it.

00:12:44.500 | So we have some interesting ones to go for.

00:12:46.040 | - Eventually both the students and the professors

00:12:48.020 | will be replaced by ChatGPT.

00:12:49.760 | - Yeah.

00:12:50.600 | - And we'll sit on the beach.

00:12:51.920 | - I really recommend, I don't know if you've ever seen them,

00:12:54.640 | it's called The Day the Universe Changed.

00:12:57.360 | - Is that a movie? - James Burke.

00:12:59.600 | He's a science historian based in the UK.

00:13:02.960 | He had a fairly famous series on public television

00:13:07.200 | called Connections, I think it was,

00:13:08.800 | but the one that I really enjoyed

00:13:10.600 | was The Day the Universe Changed.

00:13:12.960 | And the reason for the title of it was that,

00:13:18.000 | he says the universe is what we know and perceive of it.

00:13:22.680 | So when there's a fundamental insight as to something new,

00:13:26.320 | the universe for us changes.

00:13:28.320 | Of course, the universe from an objective point of view

00:13:30.440 | is the same as it was before, but for us it has changed.

00:13:33.360 | So he walks through these moments of perception

00:13:37.600 | in the history of humanity that like changed what we were.

00:13:41.920 | And so as I was thinking about coming to discuss this,

00:13:46.880 | people see fusion, oh, it's still far away,

00:13:48.960 | or it's been slow progress.

00:13:51.360 | It's like when my godmother was born,

00:13:55.280 | people had no idea how stars worked.

00:13:58.080 | So you talk about that day, that insight,

00:14:01.560 | the universe changed, it's like, oh, this is the,

00:14:04.560 | I mean, and they still didn't understand

00:14:06.040 | all the parts of it, but they basically got it.

00:14:08.800 | It's like, oh, because of the understanding

00:14:13.040 | of these processes, it's like we unveiled the reason

00:14:16.160 | that there can be life in the universe.

00:14:18.280 | That's probably one of those days

00:14:19.600 | the universe changed, right?

00:14:21.400 | And that was in the 1930s.

00:14:23.800 | - It seems like technology is developing

00:14:25.400 | faster and faster and faster.

00:14:26.920 | I tend to think, just like with Chad GPT,

00:14:30.120 | I think this year might be extremely interesting

00:14:32.860 | just with how rapid and how profitable

00:14:36.740 | the efforts in artificial intelligence are

00:14:39.060 | that just stuff will happen where our whole world

00:14:41.960 | is transformed like this, and there's a shock,

00:14:45.780 | and then the next day you kind of go on

00:14:47.480 | and you adjust immediately.

00:14:48.840 | You probably won't have a similar kind of thing

00:14:51.480 | with nuclear fusion with energy,

00:14:53.960 | 'cause there's probably going to be

00:14:55.880 | an opening ceremony and stuff.

00:14:58.240 | An announcement, it'll take months.

00:15:00.120 | But with digital technology, you can just have

00:15:02.560 | a immediate transformation of society,

00:15:05.560 | and it'll be this gasp, and then you kind of adjust,

00:15:08.840 | like we always do, and then you don't even remember,

00:15:11.160 | just like with the internet and so on,

00:15:12.720 | how the days were before.

00:15:14.080 | - And how it worked before, right.

00:15:16.060 | I mean, fusion will be, because it's energy,

00:15:18.900 | it's nature is that it will be,

00:15:21.300 | and anything that has to do with energy use

00:15:22.900 | tends to be a slower transition,

00:15:25.020 | but they're the most, I would argue,

00:15:27.140 | some of the most profound transitions that we make.

00:15:30.100 | I mean, the reason that we can live like this

00:15:33.900 | and sit in this building and have this podcast

00:15:36.180 | and people around the world is, at its heart,

00:15:38.300 | is energy use, and it's intense energy use

00:15:41.340 | that came from the evolution of starting

00:15:43.180 | to use intense energies at the beginning

00:15:44.920 | of the Industrial Revolution up to now.

00:15:47.000 | It's a bedrock, actually, of all of these,

00:15:50.560 | but it doesn't tend to come overnight.

00:15:53.040 | - Yeah, and some of the most important,

00:15:55.040 | some of the most amazing technology

00:15:56.320 | is one we don't notice, 'cause we take it for granted,

00:15:58.240 | 'cause it enables this whole thing.

00:16:00.040 | - Yeah, exactly, which is energy,

00:16:02.160 | which is amazing for how fundamental it is

00:16:05.920 | to our society and way of life

00:16:07.840 | is a very poorly understood concept, actually.

00:16:11.480 | Just even energy itself, people confuse energy sources

00:16:15.700 | with energy storage, with energy transmission.

00:16:18.260 | These are different physical phenomena,

00:16:21.740 | which are very important.

00:16:23.380 | So, for example, you buy an electric car,

00:16:26.580 | and you go, "Oh, good, I have an emission-free car."

00:16:29.380 | And, ah, but it's like, so why do you say that?

00:16:34.180 | Well, it's 'cause if I draw the circle around the car,

00:16:36.380 | I have electricity, and it doesn't emit anything.

00:16:39.780 | Okay, but you plug that into a grid

00:16:41.560 | where you follow that wire back,

00:16:43.360 | there could be a coal power plant,

00:16:45.080 | or a gas power plant at the end of that.

00:16:47.520 | Oh, really?

00:16:48.720 | You mean, so this isn't carbon-free?

00:16:50.480 | Oh, and it's not their fault, it's just,

00:16:53.640 | they don't, the car isn't a source of energy.

00:16:57.160 | The underlying source of energy

00:16:58.520 | was the combustion of the fuel back somewhere.

00:17:01.160 | - Plus, there's also a story of how the raw materials

00:17:04.680 | are mined in which parts of the world,

00:17:08.000 | with sort of basic respect or deep disrespect

00:17:11.180 | of human rights, that happens in that mining.

00:17:12.940 | So, the whole supply chain, there's a story there

00:17:15.380 | that's deeper than just a particular electric car

00:17:17.580 | with a circle around it.

00:17:18.420 | - And the physics, or the science of it, too,

00:17:20.260 | is the energy use that it takes to do that digging up,

00:17:23.300 | which is also important and all that.

00:17:25.300 | Yeah, anyway, so.

00:17:26.900 | - Yeah.

00:17:27.740 | - We wandered away from fusion, but yes.

00:17:28.820 | - Oh, it's a beautiful stroll.

00:17:29.660 | - But it's very important, actually,

00:17:31.820 | in the context of this, just because,

00:17:34.620 | you know, those of us who work in fusion

00:17:36.740 | and these other kinds of disruptive energy technologies,

00:17:41.740 | it's interesting, I do think about what is it going to mean

00:17:46.180 | to society to have an energy source that is like this,

00:17:50.260 | that would be like fusion, which has such

00:17:53.300 | completely different characteristics.

00:17:55.280 | For example, free, unlimited access to the fuel,

00:17:59.780 | but it has technology implications.

00:18:01.900 | So, what does this mean geopolitically?

00:18:03.560 | What does it mean for how we distribute wealth

00:18:06.660 | within our society?

00:18:08.020 | It's very difficult to know, but probably profound.

00:18:12.620 | - Yeah, we're gonna have to find another reason

00:18:14.220 | to start wars instead of resources.

00:18:18.140 | We're gonna have to figure something out.

00:18:18.980 | - We've done a pretty good job of that

00:18:20.300 | over the course of our histories, yeah.

00:18:23.380 | - So, we talked about the forces of physics,

00:18:26.020 | and again, sticking to the philosophical

00:18:27.940 | before we get to the specific technical stuff.

00:18:31.180 | E equals MC squared, you mentioned.

00:18:32.700 | How amazing is that to you,

00:18:34.020 | that energy and mass are the same?

00:18:36.700 | And what does that have to do with nuclear fusion?

00:18:39.140 | - So, it has to do with everything we do.

00:18:40.660 | It's the fact that energy and mass

00:18:42.740 | are equivalent to each other.

00:18:44.900 | The way we usually comment to it

00:18:46.620 | is that they're just energy, just in different forms.

00:18:49.420 | - Can you intuitively understand that?

00:18:51.980 | - Yes, but it takes a long time.

00:18:54.400 | (laughing)

00:18:56.660 | Often, I teach the introductory class

00:19:03.720 | for incoming nuclear engineers,

00:19:05.740 | and so we put this up as an equation,

00:19:08.460 | and we go through many iterations of using this,

00:19:12.120 | how you derive it, how you use it, and so forth.

00:19:15.940 | And then, usually, in the final exam,

00:19:18.460 | I would basically take all the equations

00:19:21.220 | that I've used before, and I flip it around.

00:19:23.180 | Basically, instead of thinking about energy

00:19:25.740 | is equal to mass, it's sort of mass is equal to energy.

00:19:28.620 | And I ask the question a different way,

00:19:30.800 | and usually about half the students don't get it.

00:19:32.820 | It takes a while to get that intuition, yeah.

00:19:36.620 | So, in the end, it's interesting is that

00:19:39.500 | this is actually the source of all free energy,

00:19:42.460 | because that energy that we're talking about

00:19:43.980 | is kinetic energy, if it can be transformed from mass.

00:19:47.540 | So, it turns out, even though we used equals mc squared,

00:19:51.820 | this is burning coal and burning gas,

00:19:55.140 | and burning wood is actually still equals mc squared.

00:19:58.540 | The problem is that you would never know this

00:20:00.540 | because the relative change in the mass is incredibly small.

00:20:04.260 | By the way, which comes back to fusion,

00:20:05.860 | which is that e equals mc squared.

00:20:08.340 | Okay, so what does this mean?

00:20:09.500 | It tells you that the amount of energy

00:20:11.980 | that is liberated in a particular reaction

00:20:14.540 | when you change mass has to,

00:20:16.740 | because c squared, that's the speed of light squared.

00:20:19.220 | - It's a large number.

00:20:20.060 | - It's a very large number, and it's totally constant

00:20:22.100 | everywhere in the universe, which is--

00:20:23.500 | - Which is another weird thing.

00:20:24.460 | - Which is another weird thing, and in all rest frames,

00:20:26.300 | and actually, the relativity stuff

00:20:28.260 | gets more difficult conceptually until you get through.

00:20:32.420 | Anyway, so you go to that, and what that tells you

00:20:36.980 | is that it's the relative change in the mass

00:20:40.300 | will tell you about the relative amount of energy

00:20:42.180 | that's liberated, and this is what makes fusion,

00:20:44.820 | and you asked about fission as well, too.

00:20:46.260 | This is what makes them extraordinary.

00:20:49.020 | It's because the relative change in the mass

00:20:51.420 | is very large as compared to what you get

00:20:54.420 | like in a chemical reaction.

00:20:56.060 | In fact, it's about 10 million times larger,

00:20:59.020 | and that is at the heart of why you use

00:21:03.620 | something like fusion.

00:21:04.780 | It's because that is a fundamental of nature.

00:21:08.380 | Like, you can't beat that, so whatever you do,

00:21:11.980 | if you're thinking about, and why do I care about this?

00:21:14.320 | Well, 'cause mass is like the fuel, right?

00:21:17.460 | So this means gathering the resources that it takes

00:21:20.340 | to gather a fuel, to hold it together, to deal with it,

00:21:23.820 | the environmental impact it would have,

00:21:26.340 | and fusion will always have 20 million times

00:21:29.700 | the amount of energy release per reaction

00:21:32.780 | that you could have, though.

00:21:33.620 | So this is why we consider it the ultimate

00:21:36.460 | like environmentally friendly energy source

00:21:38.740 | is because of that.

00:21:40.180 | - So is it correct to think of mass broadly

00:21:44.320 | as a kind of storage of energy?

00:21:46.020 | - Yes.

00:21:47.580 | - You mentioned it's environmentally friendly,

00:21:49.420 | so nuclear fusion is a source of energy.

00:21:52.960 | It's cheap, clean, safe, so easy access to fuel

00:21:56.380 | and virtually unlimited supply,

00:21:57.500 | no production of greenhouse gases,

00:21:59.380 | little radioactive waste produced allegedly.

00:22:03.180 | Can you sort of elaborate why it's cheap, clean, and safe?

00:22:07.700 | - I'll start with the easiest one, cheap.

00:22:09.460 | It is not cheap yet, because it hasn't been made

00:22:12.460 | at a commercial scale.

00:22:13.980 | - Time flies when you're having fun, but yes.

00:22:15.700 | - Yeah, yeah.

00:22:16.540 | (laughing)

00:22:18.420 | - But yes, not yet.

00:22:19.540 | We'll talk about that.

00:22:20.380 | - Actually, we'll come back to that

00:22:21.940 | because this is cheaper, or a more technically correct term,

00:22:26.940 | that it's economically interesting

00:22:29.820 | is really the primary challenge, actually,

00:22:33.260 | of fusion at this point.

00:22:34.800 | But I think we can get back to that.

00:22:36.900 | So what were the other ones you said?

00:22:38.460 | - So cheap, actually, when we're talking about cheap,

00:22:41.380 | we're thinking like asymptotically.

00:22:43.460 | If you take it forward several hundred years,

00:22:47.220 | that's sort of because of how much availability

00:22:51.380 | there is of resources to use.

00:22:52.900 | - Of the fuel.

00:22:53.740 | - Yeah, of the fuel.

00:22:54.560 | - We should separate those two.

00:22:55.860 | The fuel is already cheap.

00:22:58.220 | It's basically free, right?

00:23:00.260 | What do you mean by basically free?

00:23:01.700 | So if we were to be using fusion fuel sources

00:23:06.180 | to power your, and it's like, that's all we had

00:23:09.380 | was fusion power plants around, and we were doing it,

00:23:11.660 | the fuel cost per person are something like 10 cents a year.

00:23:15.340 | It's free, okay?

00:23:17.460 | This is why it's hard to, in some ways, I think,

00:23:20.060 | it's hard to understand fusion,

00:23:21.780 | because people see this and go,

00:23:23.140 | "Oh, if the fuel is free,

00:23:24.540 | "this means the energy source is free,"

00:23:26.660 | because we're used to energy sources like this.

00:23:29.140 | So we spend resources and drill to get gas or oil,

00:23:33.720 | or we chop wood, or we find coal, or these things, right?

00:23:38.100 | So fusion, this is what makes fusion,

00:23:40.740 | and it's also, it's not an intermittent,

00:23:43.800 | renewable energy source, like wind and solar.

00:23:46.300 | So it's like, but this makes it hard to understand.

00:23:48.580 | So if you're saying the fuel is free,

00:23:50.140 | why isn't the energy source free?

00:23:53.740 | And it's because of the necessary technologies

00:23:57.220 | which must be applied to basically recreate the conditions

00:24:01.580 | which are in stars, in the center of stars, in fact.

00:24:05.300 | So there's only one natural place in the universe

00:24:07.940 | that fusion energy occurs that's in the center of stars.

00:24:12.700 | So that's going to bring a price to it,

00:24:15.320 | depending on the size and complexity of the technology

00:24:20.320 | that's needed to recreate those things.

00:24:22.760 | - And we'll talk about the details of those technologies

00:24:25.080 | and which parts might be expensive today

00:24:27.480 | and which parts might be expensive in 200 years.

00:24:29.840 | - Exactly.

00:24:30.880 | It will have a revolution, I'm certain of it.

00:24:34.440 | So about clean, so clean is, at its heart,

00:24:37.700 | what it does is it basically converts hydrogen into,

00:24:41.880 | it's heavier forms of hydrogen,

00:24:44.280 | the most predominant one that we use on earth,

00:24:48.440 | and converts it into helium and some other products,

00:24:51.560 | but primarily helium is the product that's left behind.

00:24:54.120 | So helium, safe, inert, gas, you know.

00:24:57.760 | In fact, that's actually what our sun is doing.

00:24:59.960 | It's eventually going to extinguish itself

00:25:01.700 | because it'll just make so much helium

00:25:03.720 | that it doesn't do that.

00:25:05.040 | So in that sense, clean because there's no emissions

00:25:09.640 | of carbon or pollutants that come directly

00:25:12.840 | from the combustion of the fuel itself.

00:25:15.520 | - And safe.

00:25:16.640 | - Safe, yeah.

00:25:18.360 | - We're talking about very high temperatures.

00:25:19.840 | - Yeah, yeah, so this is also the counterintuitive thing.

00:25:22.760 | So I told you temperatures, which like 50 million degrees,

00:25:26.280 | or it actually tends to be more like

00:25:28.040 | about 100 million degrees is really what we aim for.

00:25:31.200 | So how can 100 million degrees be safe?

00:25:33.760 | And it's safe because this is so much hotter

00:25:38.760 | than anything on earth, where everything on earth

00:25:41.580 | is at around 300 Kelvin, you know,

00:25:43.500 | it's around a few tens of degrees Celsius.

00:25:46.440 | And what this means is that in order to get a medium

00:25:50.560 | to those temperatures, you have to completely isolate it

00:25:53.900 | from anything to do with terrestrial environment.

00:25:56.880 | It can have no contact like with anything on earth,

00:25:59.920 | basically.

00:26:00.840 | So this means what we, this is the technology

00:26:03.800 | that I just described, is it fundamentally what it does

00:26:06.800 | is it takes this fuel and it isolates it

00:26:10.380 | from any terrestrial conditions so that it has no idea

00:26:13.040 | it's on earth, it's not touching any object

00:26:15.160 | that's at room temperature.

00:26:16.800 | - Including the walls of the containment.

00:26:18.680 | - Even including the walls of the containment building

00:26:21.280 | or containment device, or even air or anything like this.

00:26:24.880 | So it's that part that makes it safe,

00:26:29.880 | and there's actually another aspect to it,

00:26:31.760 | but that fundamental part makes it so safe.

00:26:36.120 | And the main lines approach to fusion

00:26:39.940 | is also that it's very hot,

00:26:42.220 | but there's very, very few particles at any time

00:26:46.580 | in the thing that would be the power plant.

00:26:48.900 | Actually, the more correct way to do it is you say,

00:26:51.100 | there's very few particles per unit volume.

00:26:54.420 | So in a cubic centimeter and a cubic meter,

00:26:56.580 | something like that, so we can do this.

00:26:57.580 | So right now we're, although we don't think of air really

00:27:00.700 | as a, there's atoms floating around us

00:27:02.920 | and there's a density, 'cause if I wave my hand,

00:27:05.660 | I can feel the air pushing against my face.

00:27:08.240 | That means we're in a fluid or a gas, which is around us,

00:27:11.540 | that has a particular number of atoms per cubic meter.

00:27:15.980 | So it's what, this actually turns out to be 10 to the 25th.

00:27:19.900 | So this is one with 25 zeros behind it per cubic meter.

00:27:23.980 | So we can figure out like cubic meters about like this,

00:27:27.500 | the volume of this table, like the whole volume of this table.

00:27:30.700 | Okay, very good.

00:27:31.620 | So like fusion, there's a few of those.

00:27:34.620 | So fusion, like the mainstream one of fusion,

00:27:36.940 | like what we're working on at MIT,

00:27:38.660 | we'll have a hundred thousand times less particles

00:27:41.860 | per unit volume than that.

00:27:45.220 | So this is very interesting because it's extraordinarily hot

00:27:48.420 | a hundred million degrees, but it's very tenuous.

00:27:51.560 | And what matters from the engineering and safety point

00:27:55.020 | of view is the amount of energy

00:27:57.740 | which is stored per unit volume,

00:28:00.500 | because this tells you about the scenarios

00:28:04.220 | and that's what you worry about.

00:28:05.660 | 'Cause when those kinds of energies are released suddenly,

00:28:09.180 | it's like, what would be the consequences, right?

00:28:11.580 | So the consequences of this are essentially zero

00:28:14.700 | because that's less energy content than boiling water.

00:28:18.800 | Because of the low density.

00:28:21.780 | Because of the low density.

00:28:22.860 | So if you take water is at about a hundred million

00:28:26.780 | to a billion times more dense than this.

00:28:29.940 | So even though it's at much lower temperature,

00:28:33.160 | it's actually still, it has more energy content.

00:28:36.100 | So for this reason, one of the ways that I explain this

00:28:39.980 | is that if you imagine a power plant

00:28:41.660 | that's like powering Cambridge, Massachusetts,

00:28:44.500 | like if you were to, which you wouldn't do this directly,

00:28:47.220 | but if you went like this on it,

00:28:49.220 | it actually extinguishes the fusion

00:28:52.100 | because it gets too cold immediately.

00:28:55.700 | Yeah, so that's the other one.

00:28:57.380 | And the other part is that it does not,

00:28:59.420 | because it works by staying hot

00:29:02.420 | rather than a chain reaction, it can't run out of control.

00:29:05.360 | That's the other part of it.

00:29:06.260 | So by the way, this is what very much

00:29:08.720 | distinguishes it from fission.

00:29:10.160 | It's not a process that can run away from you

00:29:12.320 | 'cause it's basically thermally stable.

00:29:15.240 | - What does thermally stable mean?

00:29:16.400 | - That means is that you want to run it

00:29:18.180 | at the optimization in temperature

00:29:20.480 | such that if it deviates away from that temperature,

00:29:22.800 | the reactivity gets lower.

00:29:24.920 | And the reason for this is because it's hard

00:29:27.000 | to keep the reactivity going.

00:29:28.720 | Like it's a very hard fire to keep going, basically.

00:29:31.520 | - Oh, so it doesn't run away from you.

00:29:33.340 | - It can't run away from you.

00:29:34.500 | - How difficult is the control there to keep it at that?

00:29:37.220 | - It varies from concept to concept,

00:29:39.820 | but in generally it's fairly easy to do that.

00:29:43.880 | And the easiest thing, it can't physically run away from you

00:29:47.260 | because the other part of it is that there's just,

00:29:49.420 | at any given time, there's a very, very small amount

00:29:52.220 | of fuel available to fuse anyway.

00:29:55.320 | So this means that that's always

00:29:57.540 | intrinsically limited to this.

00:29:58.900 | So even if the power consumption of the device goes up,

00:30:02.640 | it just kind of burns itself out immediately.

00:30:05.440 | - So you are the, just to take another tangent on a tangent,

00:30:08.660 | you're the director of MIT's Plasma Science

00:30:10.660 | and Fusion Center.

00:30:11.500 | - That's right.

00:30:12.320 | - We'll talk about, maybe you can mention

00:30:15.260 | some interesting aspects of the history of the center

00:30:18.780 | in the broader history of MIT,

00:30:22.380 | and maybe broader history of science and engineering

00:30:24.740 | in the history of human civilization.

00:30:26.300 | But also just the link on the safety aspect.

00:30:29.620 | How do you prevent some of the amazing reactors

00:30:36.980 | that you're designing, how do you prevent

00:30:39.900 | from destroying all of human civilization in the process?

00:30:42.900 | What's the safety protocols?

00:30:44.380 | - Fusion is interesting 'cause it's not really

00:30:47.780 | directly weaponizable, because what I mean by that

00:30:51.380 | is that you have to work very hard to make these conditions

00:30:55.660 | at which you can get energy gain from fusion.

00:30:58.940 | And this means that when we design these devices

00:31:04.660 | with respect to application in the energy field,

00:31:07.860 | is that they, you know, while they will,

00:31:12.860 | because they're producing large amounts of power

00:31:15.660 | and they will have hot things inside of them,

00:31:17.500 | this means that they have like a level of industrial hazard,

00:31:20.700 | which is very similar to what you would have

00:31:22.540 | like in a chemical processing plant

00:31:24.540 | or anything like that, and any kind of energy plant

00:31:27.020 | actually has these as well too.

00:31:29.340 | But the underlying, underneath it, core technology

00:31:32.940 | can't be directly used in a nefarious way

00:31:37.260 | because of the power that's being emitted.

00:31:39.140 | It just basically, if you try to do those things,

00:31:42.100 | typically it just stops working.

00:31:43.580 | - So the safety concerns have to do

00:31:44.980 | with just regular things that, like equipment malfunctioning,

00:31:48.680 | melting of, like all this kind of stuff

00:31:52.620 | that has nothing to do with fusion necessarily.

00:31:54.940 | - I mean, usually what we worry about is the viability,

00:31:58.060 | 'cause in the end we build pretty complex objects

00:32:01.260 | to realize these requirements.

00:32:03.320 | And so what we try really hard to do

00:32:05.580 | is like not damage those components,

00:32:07.820 | but those are things which are internal

00:32:09.460 | to the fusion device.

00:32:11.580 | And this is not something that you would consider about,

00:32:16.220 | like it would, as you say, destroy human civilization

00:32:18.940 | because that release of energy is just inherently limited

00:32:22.020 | because of the fusion process.

00:32:23.740 | So it doesn't say that there's zero,

00:32:25.340 | so you asked about the other feature of it, that it's safe.

00:32:27.620 | So it is, the process itself is intrinsically safe,

00:32:31.580 | but because it's a complex technology,

00:32:33.860 | you still have to take into consideration aspects

00:32:36.740 | of the safety.

00:32:37.940 | So it produces ionizing radiation instantaneously.

00:32:41.660 | So you have to take care of this,

00:32:42.940 | which means that you shield it.

00:32:44.700 | Think of like your dental x-rays

00:32:46.340 | or treatments for cancer and things like this.

00:32:48.620 | We always shield ourselves from this.

00:32:50.860 | So we get the beneficial effects,

00:32:52.340 | but we minimize the harmful effects of those.

00:32:54.660 | So there are all those aspects of it as well too.

00:32:58.060 | - So we'll return to MIT's Plasma Science and Fusion Center,

00:33:01.300 | but let us linger on the destruction of human civilization,

00:33:05.100 | which brings us to the topic of nuclear fission.

00:33:07.780 | What is that?

00:33:09.000 | So the process that is inside nuclear weapons

00:33:13.820 | and current nuclear power plants.

00:33:16.060 | - So it relies on the same underlying physical principle,

00:33:20.540 | but it's exactly the opposite,

00:33:22.940 | which actually the names imply.

00:33:24.300 | Fusion means bringing things together.

00:33:26.580 | Fission means splitting things apart.

00:33:28.780 | So fission requires the heaviest instead of the lightest

00:33:33.780 | and the most unstable versus the most stable elements.

00:33:38.980 | So this tends to be uranium or plutonium,

00:33:42.180 | primarily uranium.

00:33:43.140 | So take uranium.

00:33:44.700 | So uranium-235 is one of the,

00:33:47.020 | this is one of the heaviest unstable elements.

00:33:49.400 | And what happens is that this is,

00:33:53.420 | fission is triggered by the fact

00:33:54.900 | that one of these subatomic particles,

00:33:56.540 | the neutron, which has no electric charge,

00:33:58.940 | basically gets in proximity enough to this

00:34:02.080 | and triggers an instability effectively inside of this,

00:34:06.140 | what is teetering on the border of instability

00:34:09.740 | and basically splits it apart.

00:34:11.440 | And that's the fission, right?

00:34:13.780 | The fissioning.

00:34:15.140 | And so when that happens,

00:34:17.380 | because the products that are,

00:34:19.940 | it roughly splits in two, but it's not even that,

00:34:23.220 | it's actually more complicated.

00:34:24.140 | It splits into this whole array

00:34:25.480 | of lighter elements and nuclei.

00:34:28.180 | And when that happens,

00:34:30.140 | there's less rest mass left than the original one.

00:34:35.140 | So it's actually the same.

00:34:38.020 | So it's, again, it's rearrangement

00:34:39.540 | of the strong nuclear force that's happening,

00:34:42.200 | but that's the source of the energy.

00:34:44.860 | And so in the end, it's like,

00:34:46.260 | so this is a famous graph that we show everybody

00:34:49.420 | is basically, it turns out every element

00:34:52.660 | that exists in the periodic table,

00:34:54.260 | all the things that make up everything,

00:34:56.160 | have a, remember you asked a good question.

00:34:59.380 | It was like, so should we think of mass

00:35:01.220 | as being the same as stored energy?

00:35:03.100 | Yes.

00:35:04.100 | So you can make a plot that basically shows

00:35:06.900 | the relative amount of stored energy

00:35:10.140 | in all of the elements that are stable

00:35:12.380 | and make up basically the world, okay, and the universe.

00:35:15.420 | And it turns out that this one has a maximum amount

00:35:19.580 | of stability or storage at iron.

00:35:22.780 | So it's kind of in the middle of the periodic table

00:35:26.420 | because this goes from, it's roughly that.

00:35:29.660 | And so this, what that means is that

00:35:33.060 | if you take something heavier than iron,

00:35:36.500 | like uranium, which is more than twice as heavy than that,

00:35:40.100 | and you split apart, if somehow just magically,

00:35:42.340 | you can just split apart its constituents

00:35:43.820 | and you get something that's lighter,

00:35:45.300 | that will, because it moves to a more stable energy state,

00:35:48.340 | it releases kinetic energy.

00:35:49.500 | That's the energy that we use.

00:35:51.580 | Kinetic energy meaning the movement of things.

00:35:53.700 | So it's actually an energy you can do something with.

00:35:55.980 | And fusion, it sits on the other side of that

00:35:58.860 | because it's also moving towards iron,

00:36:01.760 | but it has to do it through fusion together.

00:36:05.200 | So this leads to some pretty profound differences.

00:36:08.520 | As I said, they have some underlying physics

00:36:11.820 | or science proximity to each other,

00:36:15.700 | but they're literally the opposite.

00:36:16.900 | So fusion, why is this?

00:36:18.860 | It actually goes in the practical implications of it,

00:36:21.080 | which is that fission can happen at room temperature.

00:36:24.140 | It's because this neutron has no electric charge

00:36:28.180 | and therefore it's literally room temperature neutrons

00:36:31.460 | that actually trigger the reaction.

00:36:32.940 | So this means in order to establish what's going on with it

00:36:37.940 | and it works by a chain reaction,

00:36:39.860 | is that you can do this at room temperature.

00:36:41.460 | So Enrico Fermi did this like on a university campus,

00:36:45.540 | University of Chicago campus.

00:36:47.180 | The first sustained chain reaction was done

00:36:49.860 | underneath a squash court with a big blocks of graphite.

00:36:53.820 | It was still, don't get me wrong,

00:36:55.420 | an incredible human achievement, right?

00:36:57.740 | But that's, and then you think about fusion,

00:37:00.060 | I have to build a contraption of some kind

00:37:02.460 | that's going to get to a hundred million degrees.

00:37:04.380 | Okay, wow, that's a big difference.

00:37:06.660 | The other one is about the chain reaction,

00:37:08.960 | that namely fission works by the fact

00:37:11.300 | that when that fission occurs,

00:37:13.460 | it actually produces free neutrons.

00:37:16.220 | Free neutrons, particularly if they get slowed down

00:37:18.700 | to room temperature, can trigger other fission reactions

00:37:22.700 | if there's other uranium nearby or fissile materials.

00:37:26.340 | So this means that the way that it releases energy

00:37:28.700 | is that you set this up in a very careful way

00:37:31.580 | such that every, on average, every reaction that happens

00:37:35.980 | exactly releases enough neutrons and slows down

00:37:38.420 | that they actually make another reaction,

00:37:40.540 | one, exactly one.

00:37:42.340 | And what this means is that because each reaction

00:37:44.500 | releases a fixed amount of energy,

00:37:46.980 | you do this and then in time,

00:37:48.260 | this looks like just a constant power output.

00:37:50.220 | So that's how a fission power plant works.

00:37:52.060 | - And so their control of the chain reactions

00:37:54.540 | is extremely difficult and extremely important for--

00:37:56.900 | - It's very important.

00:37:58.000 | And when you intentionally design it,

00:37:59.660 | that it creates more than one fission reaction

00:38:03.580 | per starting reaction, then it exponentiates away.

00:38:07.160 | Which is what a nuclear weapon is.

00:38:10.380 | - Yeah, so how does an atomic weapon work?

00:38:12.620 | How does a hydrogen bomb work?

00:38:14.700 | Asking for a friend.

00:38:15.740 | - Yeah. (laughs)

00:38:17.700 | Yeah, so at its heart, what you do is you very quickly

00:38:22.580 | put together enough of these materials

00:38:25.060 | that can undergo fission with room temperature neutrons.

00:38:28.340 | And you put them together fast enough that what happens

00:38:30.860 | is that this process can essentially grow mathematically,

00:38:35.060 | like very fast.

00:38:36.380 | And so this releases large amounts of energy.

00:38:39.060 | So that's the underlying reason that it works.

00:38:42.420 | So you've heard of a fusion weapon.

00:38:44.380 | So this is interesting is that it is,

00:38:46.260 | but it's dislike fusion energy in the sense

00:38:48.860 | that what happens is that you're using fusion reactions

00:38:53.420 | but it simply, it increases the gain actually of the weapon

00:38:56.860 | rather than, it's not a pure,

00:39:00.140 | at its heart, it's still a fission weapon.

00:39:02.900 | You're just using fusion reactions

00:39:04.800 | as a sort of intermediate catalyst

00:39:06.780 | basically to get even more energy out of it.

00:39:10.220 | But it's not directly applicable

00:39:11.660 | to be used in an energy source.

00:39:14.780 | - Does it terrify you, just again,

00:39:17.260 | to step back at the philosophical,

00:39:19.340 | that humans have been able to use physics

00:39:21.940 | and engineering to create such powerful weapons?

00:39:26.940 | - I wouldn't say terrify.

00:39:29.820 | I mean, we should be, this is the progress of humanity.

00:39:35.180 | Every time that we've gotten access,

00:39:37.700 | you talk, you know, the day the universe changed.

00:39:40.100 | It was really changed when we got access

00:39:42.300 | to new kinds of energy sources.

00:39:44.180 | But every time you get access,

00:39:45.420 | and typically what this meant was you get access

00:39:48.840 | to more intense energy, right?

00:39:50.780 | And that's what that was.

00:39:52.100 | And so the ability to move from burning wood

00:39:55.220 | to using coal, to using gasoline and petroleum,

00:39:59.100 | and then finally to use this is that both the potency

00:40:03.860 | and the consequences are elevated around those things.

00:40:08.020 | - It's just like you said, the way that fusion,

00:40:12.140 | nuclear fusion would change the world,

00:40:14.940 | I don't think, unless we think really deeply,

00:40:17.660 | we'll be able to anticipate some of the things

00:40:19.300 | we can create.

00:40:20.180 | There's going to be a lot of amazing stuff,

00:40:22.420 | but then that amazing stuff is gonna enable

00:40:25.020 | more amazing stuff and more, unfortunately,

00:40:27.740 | or depending how you see it, more powerful weapons.

00:40:31.860 | - Well, yeah, but see, that's the thing.

00:40:33.820 | Fusion breaks that trend in the following way.

00:40:37.820 | So one of them, so fusion doesn't work on a chain reaction.

00:40:42.300 | There's no chain reaction, zero.

00:40:44.500 | So this means it cannot physically exponentiate away on you

00:40:47.820 | 'cause it works, and actually this is why star,

00:40:50.900 | by the way, we know this already,

00:40:52.660 | it's why stars are so stable,

00:40:54.380 | why most stars and suns are so stable.

00:40:56.980 | It's because they are regulated through their own temperature

00:41:01.200 | and their heating.

00:41:02.660 | Because what's happening is not that there's some

00:41:04.600 | probability of this exponentiating away,

00:41:06.900 | is that the energy that's being released by fusion

00:41:08.940 | basically is keeping the fire hot.

00:41:10.900 | And these tend to be, and when it comes down

00:41:15.020 | to thermodynamics and things like this,

00:41:16.660 | there's a reason, for example, it's pretty easy

00:41:19.180 | to keep a constant temperature, like in an oven

00:41:21.660 | and things like this, it's the same thing in fusion.

00:41:24.460 | So this is actually one of the features

00:41:26.020 | that I would argue fusion breaks the trend of this

00:41:30.700 | is that it has more energy intensity than fission on paper,

00:41:35.700 | but it actually does not have the consequences of control

00:41:40.340 | and sort of rapid release of the energy

00:41:42.780 | because it's actually, the physical system

00:41:45.700 | just doesn't want to do that.

00:41:47.980 | - We're gonna have to look elsewhere for the weapons

00:41:50.540 | with which we fight World War III.

00:41:52.500 | Fair enough.

00:41:54.860 | So what is plasma that you may or may not have mentioned?

00:42:00.460 | You mentioned ions and electrons and so on.

00:42:02.500 | So what is plasma, what is the role

00:42:03.980 | of plasma in nuclear fusion?

00:42:06.020 | - So plasma is a phase of matter or a state of matter.

00:42:09.420 | So unfortunately our schools don't,

00:42:12.820 | it's like I'm not sure why this is the case,

00:42:14.340 | but all children learn the three phases of matter, right?

00:42:18.260 | So, and what does this mean?

00:42:19.700 | So we'll take water as an example.

00:42:21.860 | So if it's cold, it's ice, it's in a solid phase, right?

00:42:26.660 | And then if you heat it up, it's the temperature

00:42:29.180 | that typically depends, sets the phase,

00:42:31.660 | although it's not only temperature.

00:42:33.900 | So you heat it up and you go to a liquid

00:42:36.260 | and obviously it changes its physical properties

00:42:38.380 | 'cause you can pour it and so forth, right?

00:42:41.060 | And then if you heat this up enough, it turns into a gas

00:42:44.220 | and a gas behaves differently because there's a very

00:42:46.900 | sudden change in the density,

00:42:48.540 | actually that's what's happening.

00:42:49.780 | So it changes by about a factor of 10,000 in density

00:42:53.060 | from the liquid phase into when you make it into steam

00:42:55.940 | at atmospheric pressure, all very good.

00:42:58.540 | Except the problem is they forgot like what happens

00:43:01.220 | if you just keep elevating the temperature.

00:43:03.420 | - You don't wanna give kids ideas.

00:43:04.940 | (laughing)

00:43:05.780 | They're gonna start experimenting

00:43:07.060 | and they're gonna start heating up the gas.

00:43:08.620 | - It's good to start doing it anyway.

00:43:09.980 | So it turns out that once you get above,

00:43:13.500 | it's approximately five or 10,000 degrees Celsius,

00:43:16.820 | then you hit a new phase of matter.

00:43:18.580 | And actually that's the phase of matter that is for all,

00:43:21.300 | pretty much all the temperatures

00:43:22.580 | that are above that as well too.

00:43:24.320 | And so what does that mean?

00:43:27.580 | So it actually changes phase,

00:43:28.940 | so it's a different state of matter.

00:43:30.380 | And the reason that it becomes a different state of matter

00:43:33.340 | is that it's hot enough that what happens is that the atoms

00:43:38.020 | that make up, remember go back to Feynman, right?

00:43:40.180 | Everything's made up of these individual things,

00:43:42.540 | these atoms.

00:43:43.660 | But atoms can actually themselves be,

00:43:46.780 | which are made of nuclei,

00:43:50.760 | which contain the positive particles in the neutrons.

00:43:54.020 | And then the electrons, which are very, very light,

00:43:57.460 | very much less mass than the nucleus,

00:44:00.580 | and that surround us, this is what makes up an atom.

00:44:03.180 | So a plasma is what happens when you start pulling away

00:44:06.860 | enough of those electrons that they're free from the ion.

00:44:10.300 | So all the atoms that make up us up

00:44:13.500 | and this water and all that,

00:44:14.760 | the electrons are in tightly bound states

00:44:16.880 | and basically they're extremely stable.

00:44:18.820 | Once you're at about 5,000 or 10,000 degrees,

00:44:21.380 | you start pulling off the electrons.

00:44:23.500 | And what this means is that now the medium that is there

00:44:27.400 | its constituent particles mostly have net charge on them.

00:44:31.660 | So why does that matter?

00:44:32.740 | It's because now this means that the particles can interact

00:44:37.540 | through their electric charge.

00:44:38.940 | In some sense they were when it was in the atoms as well too

00:44:40.860 | but now that they're free particles,

00:44:42.940 | this means that they start,

00:44:44.380 | it fundamentally changes the behavior.

00:44:46.300 | It doesn't behave like a gas,

00:44:47.500 | it doesn't behave like a solid or a liquid,

00:44:49.500 | it behaves like a plasma, right?

00:44:51.420 | And so why is it disappointing

00:44:54.680 | that we don't speak about this?

00:44:55.940 | It's because 99% of the universe is in the plasma state.

00:44:59.460 | It's called stars.

00:45:01.380 | And in fact, our own sun at the center of the sun

00:45:04.540 | is what clearly a plasma,

00:45:06.440 | but actually the surface of the sun,

00:45:08.020 | which is around 5,500 Celsius is also a plasma

00:45:11.860 | 'cause it's hot enough that is that.

00:45:14.060 | In fact, the things that you see,

00:45:15.680 | sometimes you see these pictures from the surface of the sun

00:45:18.380 | amazing like satellite photographs of like those big arms

00:45:22.620 | of things and of light coming off of the surface of the sun

00:45:25.600 | and solar flares, those are plasmas.

00:45:27.660 | - What are some interesting ways

00:45:28.780 | that this force state of matter is different than gas?

00:45:32.460 | - Let's go to how a gas works, right?

00:45:34.380 | So the reason a gas,

00:45:35.620 | and it goes back to Feynman's brilliance

00:45:37.300 | in saying that this is the most important concept.

00:45:39.620 | The reason actually solid, liquid and gas phases work

00:45:43.220 | is because the nature of the interaction

00:45:45.660 | between the atoms changes.

00:45:47.700 | And so in a gas, you can think of this as being,

00:45:50.820 | this room and the things, although you can't see them,

00:45:53.720 | is that the molecules are flying around,

00:45:57.220 | but then with some frequency,

00:45:58.660 | they basically bounce into each other.

00:46:00.940 | And when they bounce into each other,

00:46:02.780 | they exchange momentum and energy around on this.

00:46:07.380 | And so it turns out that the probability and the distances

00:46:10.900 | and the scattering of those of what they do,

00:46:13.420 | it's those interactions that set the,

00:46:17.300 | about how a gas behaves.

00:46:19.380 | So what do you mean by this?

00:46:20.480 | So for example, if I take an imaginary test particle

00:46:24.600 | of some kind, like I spray something into the air

00:46:27.400 | that's got a particular color,

00:46:28.600 | in fact, you can do it in liquids as well too,

00:46:30.680 | like how it gradually will disperse away from you,

00:46:35.120 | this is fundamentally set because of the way

00:46:38.760 | that those particles are bouncing into each other.

00:46:40.800 | - The probabilities of those particle bouncing.

00:46:43.080 | - The rate that they go at

00:46:44.400 | and the distance that they go at and so forth.

00:46:46.640 | So this was figured out by Einstein and others

00:46:48.840 | at the beginning of the Brownian motion,

00:46:51.180 | all these kinds of things.

00:46:52.260 | These were set up at the beginning of the last century

00:46:55.560 | and it was really like this great revelation.

00:46:58.100 | Wow, this is why matter behaves the way that it does.

00:47:00.900 | Like, wow.

00:47:01.740 | So, but it's really like, and also in liquids and in solids,

00:47:07.180 | like what really matters is how you're interacting

00:47:11.540 | with your nearest neighbor.

00:47:13.420 | So you think about that one,

00:47:14.860 | the gas particles are basically going around

00:47:16.580 | until they actually hit into each other though,

00:47:19.500 | they don't really exchange information.

00:47:21.380 | And it's the same in a liquid,

00:47:22.540 | you're kind of beside each other,

00:47:23.580 | but you can kind of move around.

00:47:24.780 | In a solid, you're literally like stuck

00:47:26.860 | beside your neighbor, you can't move like a man.

00:47:29.740 | Plasmas are weird in the sense is that it's not like that.

00:47:34.060 | So it's because the particles have electric charge,

00:47:37.700 | this means that they can push against each other

00:47:40.660 | without actually being in close proximity to each other.

00:47:44.260 | That's not an infinitely true statement,

00:47:47.060 | which if you go get it, it's a little bit more technical,

00:47:49.660 | but basically this means that you can start having action

00:47:52.780 | or exchange of information at a distance.

00:47:55.900 | And that's in fact the definition of a plasma

00:47:58.100 | that it says, this have a technical name,

00:48:00.100 | it's called a Coulomb collision,

00:48:01.380 | it just means that it's dictated by this force,

00:48:03.660 | which is being pushed between the charged particles,

00:48:06.560 | is that the definition of a plasma is a medium

00:48:10.580 | in which the collective behavior is dominated

00:48:13.400 | by these collisions at a distance.

00:48:16.020 | So you can imagine then this starts

00:48:18.060 | to give you some strange behaviors,

00:48:20.900 | which I could quickly talk about,

00:48:25.020 | like for example, one of the most counterintuitive ones

00:48:27.740 | is as plasmas get more hot,

00:48:31.540 | as they get higher in temperature,

00:48:33.600 | then the collisions happen less frequently.

00:48:36.000 | Like what?

00:48:38.260 | That doesn't make any sense.

00:48:39.340 | When particles go faster,

00:48:41.040 | you think they would collide more often.

00:48:43.380 | But because the particles are interacting

00:48:46.700 | through their electric field,

00:48:48.380 | when they're going faster,

00:48:49.500 | they actually spend less time

00:48:51.540 | in the influential field of each other,

00:48:53.820 | and so they talk to each other less

00:48:55.580 | in an energy and momentum exchange point of view.

00:48:58.460 | It's just one of the counterintuitive aspects of plasmas.

00:49:02.500 | - Which is probably very relevant for nuclear fusion.

00:49:06.260 | - Yes, exactly.

00:49:07.340 | - So if I can try to summarize

00:49:10.160 | what a nuclear fusion reactor is supposed to do.

00:49:14.320 | So you have, what, a couple of elements?

00:49:18.000 | What are usually the elements?

00:49:19.280 | - Usually deuterium and tritium,

00:49:20.640 | which are the heavy forms of hydrogen.

00:49:22.320 | - Hydrogen.

00:49:23.160 | You have those, and you start heating it.

00:49:25.600 | And then as you start heating it,

00:49:27.240 | I forgot the temperature you said,

00:49:28.520 | but it becomes plasma. - About 100 million.

00:49:29.760 | - No, first it becomes--

00:49:31.440 | - Oh, first it becomes plasma.

00:49:32.520 | So it's a gas, and then it turns into a plasma

00:49:35.160 | at about 10,000 degrees.

00:49:36.400 | And then so you have a bunch of electrons

00:49:38.060 | and ions flying around, and then you keep heating the thing.

00:49:41.460 | And I guess as you heat the thing,

00:49:44.700 | the ions hit each other rarer and rarer.

00:49:46.940 | - Yes.

00:49:47.780 | - So, oh man, that's not fun.

00:49:48.940 | (laughing)

00:49:49.780 | So you have to keep heating it,

00:49:51.660 | such that you have to keep hitting it

00:49:56.060 | until the probability of them colliding

00:49:58.300 | becomes reasonably high.

00:50:00.140 | - And so in terms--

00:50:01.420 | - Also on top of that, and sorry to interrupt,

00:50:03.940 | you have to prevent them from hitting the walls

00:50:07.440 | of the reactor. - Exactly, yes, exactly.

00:50:09.120 | - Somehow.

00:50:09.960 | - So you asked about the definitions

00:50:12.080 | of the requirements for fusion.

00:50:13.840 | So the most famous one, or in some sense

00:50:15.720 | the most intuitive one, is the temperature.

00:50:17.960 | And the reason for that is that you can make

00:50:20.760 | many, many kinds of plasmas that have zero fusion

00:50:23.640 | going on in them.

00:50:24.920 | And the reason for this is that the average,

00:50:27.960 | so you can make a plasma at around 10,000,

00:50:31.000 | in fact if you come, by the way,

00:50:32.480 | you're welcome to come to our laboratory

00:50:34.580 | at the PSFC, I can show you a demonstration

00:50:37.020 | of a plasma that you can see with your eyes

00:50:39.620 | and it's at about 10,000 degrees

00:50:41.300 | and you can put your hand up beside it

00:50:43.420 | and all this and it's like, and nothing,

00:50:45.100 | there's zero fusion going on.

00:50:47.460 | - So you have, sorry, what was the temperature

00:50:49.140 | of the plasma?

00:50:49.980 | - About 10,000 degrees.

00:50:50.800 | - You can stick your hand in?

00:50:51.780 | - Well, you can't stick your hand into it,

00:50:53.260 | but there's a glass tube, you can basically see this.

00:50:55.500 | - See it right there.

00:50:56.340 | - Yeah, and you can put your hand on the glass tube

00:50:58.540 | because it's--

00:50:59.380 | - What's the color, is it purple?

00:51:00.500 | - It's purple, yeah.

00:51:01.740 | - Blue and purple.

00:51:02.580 | - It's blue and purple.

00:51:03.740 | It is kind of beautiful.

00:51:05.420 | Yeah, plasmas are actually quite astonishing sometimes

00:51:08.580 | in their beauty.

00:51:09.660 | Actually, one of the most amazing forms of plasma

00:51:12.060 | is lightning, by the way, which is instantaneous form

00:51:14.860 | of plasma that exists on Earth but immediately goes away

00:51:17.860 | because everything else around it is at room temperature.

00:51:21.020 | Yeah, so there's different requirements in this.

00:51:22.900 | So making a plasma takes about this,

00:51:25.900 | but at 10,000 degrees, even at a million degrees,

00:51:29.820 | there's almost no probability

00:51:32.100 | of the fusion reactions occurring.

00:51:33.740 | And this is because while the charged particles

00:51:37.120 | can hit into each other,

00:51:38.820 | if you go back to the very beginning of this,

00:51:41.060 | remember I said, oh, these charged particles

00:51:43.860 | have to get to within distances

00:51:45.900 | which are like this size of a nucleus

00:51:49.080 | because of the strong nuclear force.

00:51:51.160 | Well, unfortunately, as the particles get closer,

00:51:56.420 | the repulsion that comes from the charge,

00:51:59.460 | the Coulomb force, increases

00:52:01.900 | like the inverse distance squared.

00:52:04.740 | So as they get closer,

00:52:06.380 | they're pushing harder and harder apart.

00:52:09.380 | So then it gets a little bit more exotic,

00:52:11.340 | which maybe you'll like though,

00:52:12.480 | that it turns out that people understood this

00:52:15.300 | at the beginning of the age

00:52:19.460 | of after Rutherford discovered the nucleus.

00:52:21.460 | It's like, oh, yeah, it's like, how are we going to,

00:52:23.500 | how is this gonna work, right?

00:52:25.220 | 'Cause how do you get anything within these distances

00:52:27.500 | is like an inquire, extraordinary energy.

00:52:30.140 | And it does, and in fact, when you look at those energies,

00:52:32.260 | they're very, very high.

00:52:33.720 | But it turns out quantum physics comes to the rescue

00:52:38.380 | because the particles aren't actually just particles,

00:52:42.180 | they're also waves.

00:52:43.400 | This is the point of quantum, right?

00:52:45.220 | You can treat them both as waves and as particles.

00:52:48.640 | And it turns out if you get,

00:52:50.540 | if they get in close enough proximity to each other,

00:52:53.620 | then the particle pops through,

00:52:58.140 | basically this energy barrier

00:52:59.780 | through an effect called quantum tunneling,

00:53:02.780 | which is really just the transposition of the fact

00:53:04.900 | that it's a wave so that it has a finite probability

00:53:07.900 | of this.

00:53:09.400 | By the way, you talk about like,

00:53:10.620 | do you have a hard time like conceptualizing this?

00:53:13.100 | These are, this is one of them.

00:53:14.460 | - Quantum tunneling is one of them?

00:53:15.300 | - Yeah, this is like throwing a ping pong ball,

00:53:17.820 | like at a piece of paper,

00:53:20.060 | and then every like, you know, 100 of them

00:53:22.180 | just like magically show up on the other side of the paper

00:53:24.820 | without seemingly breaking the paper.

00:53:26.580 | I mean, to use a physical analogy.

00:53:29.180 | - And that phenomena is critical

00:53:32.980 | for the function of nuclear fusion.

00:53:34.500 | - Yes, for all kinds of fusion.

00:53:36.620 | So this is the reason why stars can work as well too.

00:53:39.900 | Like the stars would have to be much, much hotter

00:53:42.660 | actually to be able to,

00:53:43.660 | in fact, it's not clear that they would actually ignite,

00:53:46.840 | in fact, without this effect.

00:53:48.780 | And so we get to that.

00:53:50.300 | So this is why there's another requirement.

00:53:52.900 | It's not, so you must make a plasma,

00:53:55.100 | but you also must get it very hot

00:53:57.500 | in order for the reactions to have a significant probability

00:54:00.580 | to actually fuse.

00:54:01.860 | And it actually falls effectively almost to zero

00:54:04.220 | for lower temperatures as well too.

00:54:07.060 | - So there's some nice equation

00:54:09.820 | that gets you to 50 million degrees,

00:54:12.700 | or like, or you said, practically speaking, 100 million.

00:54:17.260 | - It's a really simple equation.

00:54:18.540 | It's the ideal gas law, basically, almost.

00:54:20.540 | So in the end, you've got a certain number of particles,

00:54:24.260 | of these fusion particles in the plasma state,

00:54:26.420 | they're in the plasma state.

00:54:27.300 | There's a certain number of particles.

00:54:29.340 | And if the confinement is perfect,

00:54:30.980 | if you put in a certain content of energy,

00:54:33.020 | then basically, eventually they just,

00:54:35.240 | they come up in a temperature and they become,

00:54:37.700 | they go up to high temperature.

00:54:40.380 | This turns out to be, by the way,

00:54:42.020 | extraordinarily small amounts of energy.

00:54:45.660 | And you go, what?

00:54:46.500 | It's like, I'm getting something to like 100 million

00:54:48.660 | degrees, that's gonna take the biggest flame burner

00:54:51.340 | that I've ever seen.

00:54:52.580 | No.

00:54:54.260 | And the reason for this is it goes back

00:54:56.340 | to the energy content of this.

00:54:59.320 | So yeah, you have to get it to high average energy,

00:55:03.440 | but there's very, very few particles.

00:55:05.820 | - There's low density.

00:55:06.980 | How do you get it to be low density in a reactor?

00:55:09.380 | Is this--

00:55:10.220 | - So the way that you do this is primarily, again,

00:55:12.700 | this is not exactly true in all kinds of fusion,

00:55:15.780 | but in the primary one that we work on, magnetic fusion,

00:55:19.620 | this is all happening in a hard vacuum.

00:55:21.800 | So it's like it's happening in outer space.

00:55:23.540 | So basically, you've gotten rid of all the other particles,

00:55:26.140 | except for these specialized--

00:55:27.780 | - So you add them one at a time?

00:55:30.300 | - No, actually, it's even easier than that.

00:55:32.540 | You connect a gas valve and you basically

00:55:35.620 | leak gas into it.

00:55:36.860 | - In a controlled fashion?

00:55:37.860 | - Yeah, yeah.

00:55:38.940 | - Oh, this is beautiful.

00:55:40.140 | - It's a gas cylinder.

00:55:41.620 | - How do you get it from hitting the walls?

00:55:43.260 | - Yeah, so now you've touched on

00:55:45.260 | the other necessary requirements.

00:55:46.580 | So it turns out it's not just temperature that's required.

00:55:49.380 | You must also confine it.

00:55:51.720 | So what does this mean, confine it?

00:55:53.140 | - And there's two types of confinement, as you mentioned.

00:55:55.060 | You mentioned the magnetic one.

00:55:56.100 | - Magnetic one, and there's one called inertial as well too.

00:55:59.900 | But the general principle actually has nothing to do with,

00:56:03.060 | in particular, with what the technology is

00:56:06.340 | that you use to confine it.

00:56:08.180 | It's because this goes back to the fact

00:56:11.340 | that the requirement in this is high temperature

00:56:14.340 | and thermal content.

00:56:15.860 | So it's like building a fire.

00:56:17.360 | And what this means is that when you release the energy

00:56:22.360 | into this or apply heat to this,

00:56:25.860 | if it just instantly leaks out, it can never get hot.

00:56:29.380 | So you're familiar with this, it's like you've got

00:56:31.100 | something that you're trying to apply heat to,

00:56:33.740 | but you're just throwing the heat away very quickly.

00:56:36.380 | This is why we insulate homes, by the way,

00:56:38.180 | and things like this.

00:56:39.020 | It's like you don't want the heat that's coming

00:56:40.940 | into this room to just immediately leave

00:56:43.220 | 'cause you'll just start consuming infinite amounts

00:56:45.260 | of heat to try to keep it hot.

00:56:47.140 | So in the end, this is one of the requirements,

00:56:49.180 | and it actually has a name.

00:56:50.640 | We call it the energy confinement time.

00:56:52.980 | So this means if you release a certain amount of energy

00:56:55.580 | into this fuel, kind of how long,

00:56:59.020 | you sit there and you look at your watch,

00:57:00.500 | how long does it take for this energy

00:57:02.180 | to like leave the system?

00:57:03.420 | So you could imagine that in this room,

00:57:05.500 | that these heaters are putting energy into the air

00:57:07.860 | in this room, and you waited for a day,

00:57:10.100 | but all the heat have gone to outside.

00:57:11.860 | If I open up the windows, oh, there,

00:57:13.140 | that's energy confinement time.

00:57:14.460 | Okay, so it's the same concept as that.

00:57:16.980 | So this is an important one.

00:57:18.220 | So all fusion must have confinement.

00:57:21.500 | There's another more esoteric reason for this,

00:57:24.220 | which is that people often confuse temperature and energy.

00:57:29.060 | So what do I mean by that?

00:57:30.140 | So this is literally a temperature,

00:57:32.160 | which means that it is a system in which all the particles,

00:57:36.260 | every particle has high kinetic energy

00:57:39.680 | and is actually in a fully relaxed state,

00:57:42.260 | namely that entropy has been maximized.

00:57:44.100 | I think it's a little bit more technical,

00:57:45.400 | but this means that basically it is a thermal system.

00:57:48.860 | So it's like the air in this room,

00:57:49.980 | it's like the water, it's the water in this.

00:57:51.980 | These all have temperatures,

00:57:53.900 | which means that there's a distribution of those energies

00:57:56.060 | 'cause the particles have collided so much that it's there.

00:57:58.560 | So this is distinguished from having high energy particles,

00:58:02.860 | like what we have in like particle accelerators

00:58:04.820 | like CERN and so forth.

00:58:06.300 | Those are high kinetic energy,

00:58:09.380 | but it's not a temperature,

00:58:10.540 | so it actually doesn't count as confinement.

00:58:12.620 | So we go through all of those, you have temperature,

00:58:15.800 | and then the other requirement, not too surprising,

00:58:18.340 | is actually that there has to be enough density of the fuel.

00:58:22.860 | - Enough, but not too much.

00:58:23.700 | - Enough, but not too much, yes.

00:58:25.220 | And so in the end, the way that there's a fancy name for it,

00:58:30.140 | it's called the Lawson criterion

00:58:31.540 | because it was formulated by scientists

00:58:34.700 | in the United Kingdom about 1956 or 1957.

00:58:39.300 | And this was essentially the realization,

00:58:41.460 | oh, this is what it's going to take,

00:58:43.020 | regardless of the confinement method.

00:58:45.380 | These are, this is the basic,

00:58:46.980 | what it is actually power balances just says,

00:58:49.900 | oh, there's a certain amount of heat coming in,

00:58:52.300 | which is coming from the fusion reaction itself

00:58:54.820 | 'cause the fusion reaction heats the fuel

00:58:57.340 | versus how fast you would lose it.

00:59:00.340 | And it basically summarized,

00:59:02.340 | it's summarized by those three parameters,

00:59:04.340 | which is fairly simple.

00:59:05.360 | So temperature, and then the reason we say

00:59:08.460 | 100 million degrees is because almost all way in,

00:59:12.780 | and for this kind of fusion, deuterium-tritium fusion,

00:59:15.220 | the minimum in the density

00:59:17.060 | and the confinement time product is at about 100 million.

00:59:19.580 | So you almost always design your device around that minimum.

00:59:23.220 | And then you try to get it contained well enough

00:59:25.620 | and you try to get enough density.

00:59:26.940 | So, you know, so that temperature thing sounds crazy, right?

00:59:31.340 | That's what we've actually achieved in the laboratory.

00:59:33.460 | Like our experiment here at MIT,

00:59:35.700 | when it ran at its optimum configuration,

00:59:38.300 | it was at 100 million degrees,

00:59:40.420 | but it wasn't actually,

00:59:41.580 | the product of the density and the confinement time

00:59:44.780 | wasn't sufficient that we were at a place

00:59:46.460 | that we were getting high net energy gain,

00:59:49.180 | but it was making fusion reactions.

00:59:51.380 | So this is the sequence that you go through,

00:59:53.260 | make a plasma, then you get it hot enough.

00:59:56.180 | And when you get it hot enough,

00:59:57.360 | the fusion reactions start happening so rapidly

01:00:00.500 | that it's overcoming the rate

01:00:02.420 | that which is leaking heat to the outside world.

01:00:04.860 | And at some point it just becomes like a star,

01:00:07.660 | like a sun and our own sun and a star

01:00:10.960 | doesn't have anything plugged into it.

01:00:12.300 | It's just keeping itself hot

01:00:13.580 | through its own fusion reactions.

01:00:15.140 | In the end, that's really close

01:00:16.460 | to what a fusion power plant would look like.

01:00:17.980 | - What does it visually look like?

01:00:19.420 | Does it look like, like you said, like purple plasma?

01:00:22.940 | - Yeah, actually it's invisible to the eye

01:00:25.100 | 'cause it's so hot that it's basically emitting light

01:00:27.940 | in frequencies that we can't detect.

01:00:30.580 | It's literally, it's invisible.

01:00:32.320 | In fact, light goes through it,

01:00:34.780 | visible light goes through it so easy

01:00:36.340 | that if you were to look at it,

01:00:37.460 | what you would see in our own particular configuration,

01:00:40.860 | what we make is in the end is a donut shaped,

01:00:43.700 | it's a vacuum vessel to keep the air out of it.

01:00:46.780 | And when you turn on the plasma,

01:00:48.980 | it gets so hot that most of it just disappears

01:00:51.580 | in the visible spectrum, you can't see anything.

01:00:53.940 | And there's very, very cold plasma,

01:00:56.800 | which is between 10 and 100,000 degrees,

01:00:59.600 | which is out in the very periphery of it,

01:01:01.660 | which is kind of, so the very cold plasma

01:01:04.100 | is allowed to interact with the,

01:01:06.460 | kind of has to interact with something eventually

01:01:08.300 | at the boundary of the vacuum vessel.

01:01:10.220 | And this kind of makes a little halo around it

01:01:12.460 | and it glows as beautiful purple light basically.

01:01:15.500 | And these are, that's what we can sense

01:01:19.060 | in the human spectrum.

01:01:20.540 | - I remember reading on a subreddit called Shower Thoughts,

01:01:25.300 | which people should check out.

01:01:26.660 | It's just fascinating philosophical ideas

01:01:28.780 | that strike you while you're in the shower.

01:01:31.180 | And one of them was, it's lucky that fire,

01:01:35.420 | when it burns, communicates that it's hot

01:01:38.460 | using visible light, otherwise humans would be screwed.

01:01:41.820 | I don't know if there's a deep, profound truth to that,

01:01:44.540 | but nevertheless, I did find it on Shower Thoughts subreddit.

01:01:47.220 | - Actually, I do have, this goes off on a bit of,

01:01:51.080 | you're right, this is actually, it's interesting

01:01:53.380 | 'cause as a scientist, you also think

01:01:55.260 | about evolutionary functions and how we got,

01:01:57.460 | like why do we have the senses that we do?

01:01:59.580 | It's an interesting question.

01:02:00.780 | Like why can bees see in the ultraviolet and we can't?

01:02:03.900 | And then you go, well, it's natural selection.

01:02:05.340 | For some reason, this wasn't really

01:02:06.660 | particularly important to us, right?

01:02:08.420 | Why can't we see in the infrared and other things can?

01:02:10.620 | It's like, hmm.

01:02:11.460 | - Because the people that could.

01:02:13.940 | - It's a fascinating question, right?

01:02:15.460 | Obviously, there's some advantage that you have there

01:02:18.020 | that isn't there, and even color distinguishing, right,

01:02:20.820 | of something safe to eat, whatever it would be.

01:02:24.140 | I'll actually go back to this because it's something

01:02:26.100 | that I tell all of my students when I'm teaching

01:02:29.740 | ionizing radiation and radiological safety.

01:02:32.860 | Whatever you say, there's a cultural concern

01:02:35.740 | or that when people hear the word radiation,

01:02:38.420 | like what does this mean?

01:02:39.460 | It literally just means light is what it means, right?

01:02:43.100 | But it's light in different parts of the spectrum, right?

01:02:46.420 | And so it turns out besides the visible light

01:02:49.260 | that we can see here, we are immersed

01:02:51.940 | in almost the totality of the electromagnetic spectrum.

01:02:55.380 | There is visible light, there's infrared light,

01:02:58.040 | there is microwaves going around us.

01:03:00.180 | That's how our cell phone works.

01:03:01.300 | You can't, it's way past our detection capability.

01:03:05.300 | But also higher energy ones, which have to do

01:03:07.380 | with ultraviolet light, how you get a sunburn,

01:03:09.680 | and even x-rays and things like this at small levels

01:03:14.140 | are continually being, like from the concrete

01:03:16.260 | in the walls of this hotel, there's x-rays

01:03:18.980 | hitting our body continuously.

01:03:20.980 | I can bring out, we can go down to the lab at MIT

01:03:23.300 | and bring out a detector and show you.

01:03:24.740 | Every single room will have these.

01:03:26.860 | - By our body, you mean the 10 to the 28 atoms?

01:03:29.100 | - Yeah, the 10 to the 28 atoms,

01:03:30.700 | and they're coming in and they're interacting

01:03:32.180 | with those things.

01:03:33.380 | And those, particularly the ones where the light

01:03:35.500 | is at higher average energy per light particle,

01:03:39.640 | those are the ones that can possibly have an effect

01:03:42.100 | on human health.

01:03:43.260 | So we, it's interesting, humans and all animals

01:03:46.500 | have evolved on Earth where we're immersed

01:03:49.600 | in that all the time.

01:03:51.580 | There's a natural source of radiation all the time,

01:03:53.500 | yet we have zero ability to detect it, like zero.

01:03:57.540 | - Yeah, and our ability, cognitive ability

01:03:59.340 | to filter it all out and not give a damn.

01:04:01.340 | - It would probably overwhelm us, actually,

01:04:03.140 | if we could see all of it.

01:04:04.020 | But my main point goes back to your thing about fire

01:04:06.740 | and self-protection.

01:04:08.500 | If ionizing radiation was such a critical aspect

01:04:12.500 | of the health of organisms on Earth,

01:04:14.860 | we would almost certainly have evolved methods

01:04:16.960 | to detect it, and we have none.

01:04:18.960 | (laughing)

01:04:20.820 | Yes.

01:04:21.660 | - The physical world that's all around us,

01:04:23.020 | it's just incredible.

01:04:23.860 | You're blowing my mind, Dr. Dennis White.

01:04:26.500 | Okay, so you have experience with magnetic confinement,

01:04:30.580 | you have experience with inertial confinement.

01:04:32.140 | Most of your work has been in magnetic confinement.

01:04:34.520 | But let's sort of talk about the sexy recent thing

01:04:39.520 | for a bit of a time.

01:04:41.420 | There's been a breakthrough in the news

01:04:43.320 | that laser-based inertial confinement was used

01:04:48.220 | by DOE's National Ignition Facility

01:04:51.280 | at the Lawrence Livermore National Laboratory.

01:04:53.780 | Can you explain this breakthrough

01:04:55.080 | that happened in December?

01:04:56.060 | - Yeah, so it goes to the set of criteria

01:04:59.500 | that I talked about before about getting high energy gain.

01:05:04.500 | So in the end, what are we after in fusion

01:05:08.420 | is that we basically assemble this plasma fuel in some way,

01:05:13.420 | and we provide it a starting amount of energy,

01:05:16.300 | think of lighting the fire.

01:05:18.260 | And what you want to do is get back significant excess gain

01:05:23.620 | from the fact that the fusion is releasing the energy.

01:05:28.180 | So it's like the equivalent of we want to have a match,

01:05:31.540 | a small match, light a fire, and then the fire keeps us hot.

01:05:34.340 | It's very much like that.

01:05:36.360 | So as I said, we've made many of the,

01:05:39.780 | and what do I mean by we?

01:05:40.620 | It's like the fusion community has pursued aspects of this

01:05:43.900 | through a variety of different confinement methodologies,

01:05:46.860 | is that the key part about what happens,

01:05:53.060 | what was the threshold we had never gotten over before

01:05:55.940 | was that if you only consider the plasma fuel,

01:05:58.860 | not the total engineering system,

01:06:00.640 | but just the plasma fuel itself,

01:06:02.740 | we had not gotten to the point yet

01:06:04.420 | where basically the size of the match

01:06:07.660 | was smaller than the amount of energy

01:06:10.680 | that we got from the fusion.

01:06:12.500 | - Is there a good term for when the output

01:06:15.780 | is greater than the input?

01:06:17.140 | - Yes, yes, there is.

01:06:18.760 | Well, there's several special definitions of this.

01:06:21.580 | So one of them is that if you, like in a fire,

01:06:25.300 | if you light a match and you have it there

01:06:27.540 | and it's an infinitesimal amount of energy

01:06:29.900 | compared to what you're getting out of the fire,

01:06:31.660 | we call this ignition, which makes sense, right?

01:06:34.420 | This is like what our own sun is as well too.

01:06:37.440 | So that was not ignition in that sense as well too.

01:06:41.080 | So what we call this is scientific,

01:06:43.100 | what the one that I just talked about,

01:06:44.740 | which is for some instance,

01:06:46.820 | when I get enough fusion energy released

01:06:49.580 | compared to the size of the match,

01:06:51.780 | we call this scientific break-even.

01:06:54.300 | - Break-even.

01:06:55.140 | - Break-even, and it's because you've gotten past the fact

01:06:57.620 | that this is unity now at this point.

01:07:00.060 | - What is a fusion gain or as using the notation Q

01:07:04.260 | from the paper review of the Spark talk before,

01:07:07.300 | using just the same kind of term.

01:07:08.780 | - Yeah, actually, so that is,

01:07:09.620 | I'm sorry, the technical term is Q, capital Q.

01:07:13.700 | - Oh, so people actually use Q.

01:07:15.500 | - We actually use capital Q,

01:07:16.940 | or sometimes it's called Q.

01:07:17.780 | - So Q is taken.

01:07:18.680 | - Q sub P or something like this.

01:07:20.740 | Okay, so this is, which means,

01:07:23.380 | what it means is that it's in the plasma.

01:07:25.380 | So all we're considering is the energy balance

01:07:27.980 | or a gain that comes from the plasma itself.

01:07:30.380 | We're not considering the technologies

01:07:32.940 | which are around it,

01:07:33.820 | which are providing the containment and so forth.

01:07:36.300 | So why the excitement and so?

01:07:38.660 | Well, because for one reason,

01:07:40.460 | it's a rather simple threshold to get over

01:07:44.020 | to understand that you're getting more energy out

01:07:46.340 | from the fusion, even in a theoretical sense,

01:07:49.200 | than you were from the starting match.

01:07:52.160 | - Do you mean conceptually simple?

01:07:53.360 | - It's conceptually simple that you get past one,

01:07:55.520 | that everyone, like when you're less than one,

01:07:58.380 | that's much less interesting than getting past one.

01:08:00.600 | - So there's a really big threshold to get past.

01:08:03.820 | - But it really is a scientific threshold

01:08:06.600 | 'cause what QP actually denotes

01:08:11.240 | is the relative amount of self-heating

01:08:14.720 | that's happening in the plasma.

01:08:17.220 | So what I mean by this is that in the end,

01:08:19.700 | in these systems, what you want is something

01:08:24.700 | where the relative amount of heating,

01:08:28.780 | which is keeping the fuel hot,

01:08:30.460 | is dominated from the fusion reactions themselves.

01:08:34.260 | So it becomes, it's sort of like thinking

01:08:37.860 | like a bonfire is a lot more interesting physically

01:08:40.740 | than just holding a blowtorch to a wet log, right?

01:08:44.380 | There's a lot more dynamics,

01:08:45.620 | it's a lot more self-evolved and so forth.

01:08:48.140 | And what we're excited as scientists

01:08:50.780 | is that it's clear that in that experiment

01:08:54.580 | that they actually got to a point

01:08:56.020 | where the fusion reactions themselves

01:08:58.940 | were actually altering the state of the plasma.

01:09:01.660 | It's like, wow, I mean, we'd seen it in glimpses before

01:09:05.860 | in magnetic confinement at relatively small levels,

01:09:08.500 | but apparently it seems like in this experiment

01:09:10.780 | it's likely to be a dominant, dominated by self-heating.

01:09:14.780 | That's a very important, that's a very--

01:09:16.380 | - So that makes it a self-sustaining type of reaction.

01:09:18.500 | - It's more self-sustaining,

01:09:19.700 | it's more self-referential system in a sense.

01:09:23.420 | And it sort of self-evolves in a way.

01:09:25.340 | Again, it's not that it's gonna evolve

01:09:26.660 | to a dangerous state, it's just that we want to see

01:09:29.280 | what happens when the fusion is the dominant heating source.

01:09:32.740 | - And we'll talk about that,

01:09:33.620 | but there's also another element,

01:09:35.280 | which is the inertial confinement,

01:09:37.600 | laser-based inertial confinement.

01:09:40.020 | It's kind of a little bit of an underdog.

01:09:42.620 | So a lot of the broad nuclear fission community

01:09:45.580 | has been focused on magnetic confinement.

01:09:47.340 | Can you explain just how laser-based

01:09:50.980 | inertial confinement works?

01:09:52.140 | So it says 192 laser beams were aligned

01:09:57.140 | on a deuterium-tradium-DT target smaller than a pea.

01:10:01.380 | - Yes.

01:10:02.220 | - This is like-- - Or a bee-bee, actually.

01:10:04.380 | - Throw, okay, well, you know, it depends.

01:10:06.420 | Not all peas are made the same.

01:10:08.160 | But this is like throwing a perfect strike

01:10:10.940 | in baseball from a pitch.

01:10:12.620 | This is like a journalist wrote this, I think.

01:10:14.460 | This is like, oh, no, it's not a journalist,

01:10:15.980 | it's DOE wrote this.

01:10:16.820 | - Yeah, yeah, it could be. - Department of Energy.

01:10:18.300 | - We try to use all these analogies.

01:10:20.020 | - This is like throwing a perfect strike in baseball

01:10:23.300 | from a pitcher's mount 350 miles away from the plate.

01:10:27.060 | There you go.

01:10:27.980 | Department of Energy.

01:10:29.340 | The United States Department of Energy wrote this.

01:10:31.740 | Can you explain what the lasers--

01:10:36.100 | - What actually happens.

01:10:37.340 | Actually, there's usually mass confusion about this.

01:10:39.940 | So what's going on in this form of energy?

01:10:43.100 | So the fuel is delivered in a discrete,

01:10:47.820 | the fusion fuel, the deuterium-tradium,

01:10:50.060 | is in a discrete spherical, it's more like a bee-bee.

01:10:52.580 | Let's call it a bee-bee.

01:10:53.420 | So it's a small one.

01:10:54.780 | And all the fuel that you're gonna try to burn

01:10:57.300 | is basically there, okay?

01:10:59.140 | And it's about that size.

01:11:00.540 | So how are you going to get, and it's at,

01:11:03.660 | literally, it's like at 20 degrees above absolute zero

01:11:06.980 | because the deuterium and tradium are kept

01:11:08.820 | in a liquid and solid state.

01:11:11.700 | - Oh, wow, so the fuel is injected not as a gas,

01:11:14.060 | but as a solid.

01:11:15.260 | - It's actually, and it's very,

01:11:16.540 | and in these particular experiments,

01:11:18.340 | they can introduce one of these targets

01:11:21.420 | once per day, approximately, something like that.

01:11:23.740 | 'Cause it's very, it's a kind of amazing technology,

01:11:27.580 | actually, that I know some of the people

01:11:29.340 | that worked on this back in the,

01:11:31.020 | they actually make these things at a bee-bee size

01:11:35.640 | of this frozen fuel, it's actually at cryogenic

01:11:37.680 | temperatures, and they're almost like smooth

01:11:40.740 | to the atom level.

01:11:41.900 | I mean, they're amazing pieces of technology.

01:11:45.200 | So what you do in the end is, what you have

01:11:48.420 | is a spherical assembly of this fuel, like a ball.

01:11:53.220 | And what is the purpose of the lasers?

01:11:55.180 | The purpose of the lasers is to provide optical energy

01:11:59.340 | to the very outside of this.

01:12:01.820 | And what happens is that energy is absorbed,

01:12:06.080 | because it's in the solid phase of matter,

01:12:08.720 | so it's absorbed really in the surface.

01:12:10.880 | And then what happens is that when it's absorbed,

01:12:13.360 | and of something called the ablator, what does that mean?

01:12:16.000 | It means it goes instantly from the solid phase

01:12:19.560 | to the gas phase, so it becomes like a rocket engine.

01:12:22.960 | But you hit it very uniformly.

01:12:25.760 | So all, there's like rocket engines coming off the surface.

01:12:29.720 | Think of like an asteroid, almost,

01:12:31.340 | where there's like rockets coming off, almost.

01:12:33.760 | So what does that do?

01:12:34.600 | Well, what does a rocket do?

01:12:35.680 | It actually pushes, by Newton's laws, right?

01:12:38.800 | It pushes the other thing on the other side of it,

01:12:41.080 | equal and opposite reaction, it pushes it in.

01:12:44.120 | So what it does is that the lasers actually don't heat.

01:12:48.120 | This is what was confusing.

01:12:49.560 | People think the lasers, oh, we're gonna get it

01:12:51.320 | to 100 million degrees.

01:12:52.640 | In fact, you want the exact opposite of this.

01:12:54.400 | What you want to do is get essentially a rocket

01:12:57.360 | going out like this, and then what happens

01:13:00.120 | is that the sphere, and this is happening

01:13:02.220 | in a billionth of a second or less, actually,

01:13:04.920 | this rapidly, that force so rapidly compresses the fuel

01:13:09.920 | that what happens is that you're squeezing down on it,

01:13:12.920 | and it's like, what was the, see, BB, that's bad,

01:13:17.580 | actually, BB, I should have started with a basketball.

01:13:20.120 | Goes from like a basketball down to something like this

01:13:24.160 | in a billionth of a second.

01:13:26.160 | And when that happens, I mean, scale that in your mind.

01:13:30.160 | So when that happens, and this comes from,

01:13:33.720 | almost from classical physics,

01:13:35.000 | so there's some quantum in it as well, too,

01:13:37.000 | but basically, if you can do this very uniformly,

01:13:41.320 | and so-called adiabatically, like you're not actually

01:13:43.240 | heating the fuel, what happens is you get adiabatic

01:13:46.400 | compression such that the very center of this thing

01:13:49.280 | all of a sudden just spikes up in temperature

01:13:51.960 | because it's actually done so fast.

01:13:55.320 | So why is it called inertial fusion?

01:13:57.480 | It's because you're doing this on such fast timescales

01:14:00.760 | that the inertia of the hot fuel basically

01:14:03.600 | is still finite, so it can't push itself apart

01:14:06.440 | before the fusion happens.

01:14:08.640 | - Oh, wow, so how do you make it so fast?

01:14:12.440 | - This is why you use lasers, because you're applying

01:14:16.060 | this energy in very, very short periods of time,

01:14:19.080 | like under a fraction of a billionth of a second.

01:14:21.840 | And so basically that, and then the force,

01:14:23.960 | which is coming from this, comes from the energy

01:14:26.000 | of the lasers, which is basically the rocket action

01:14:29.520 | which does the compression.

01:14:30.800 | - So is the force, is the inward-facing force,

01:14:34.440 | is that increasing the temperature exponentially?

01:14:36.240 | - No, you wanna keep the fuel cold,

01:14:39.960 | and then just literally just ideally compress it,

01:14:43.240 | and then in something which is at the very center

01:14:45.600 | of that compressed sphere, because you've compressed it

01:14:48.600 | so rapidly, the laws of physics basically require

01:14:51.960 | for it to increase in temperature.

01:14:53.640 | - So the change in pressure.

01:14:54.480 | - The effect is like, if you know the thing,

01:14:56.880 | so adiabatic cooling we're actually fairly familiar with.

01:14:59.600 | If you take a spray can, right, and you push the button,

01:15:03.000 | when it rapidly expands, it cools.

01:15:05.840 | This is the nature of a lot of cooling technology

01:15:08.020 | we use, actually.

01:15:09.120 | Well, the opposite is true, that if you would take

01:15:11.080 | all of those particles and jam them together

01:15:13.120 | very fast back in, they wanna heat up.

01:15:15.520 | And that's what happens.

01:15:17.240 | And then what happens is you basically have this

01:15:21.120 | very cold, compressed set of fusion fuel,

01:15:24.560 | and at the center of this, it goes to this

01:15:27.200 | 100 million degrees Celsius.

01:15:29.680 | And so if it gets to that 100 million degrees Celsius,

01:15:32.120 | the fusion fuel starts to burn.

01:15:34.320 | And when that fusion fuel starts to burn,

01:15:36.160 | it wants to heat up the other cold fuel around it,

01:15:38.480 | and it just basically propagates out so fast

01:15:41.600 | that what you would do, ideally, you would actually burn,

01:15:44.720 | in a fusion sense, most of the fuel that's in the pellet.

01:15:48.000 | So this was very exciting, because what they had done

01:15:50.220 | was it's clear that they propagated this,

01:15:54.240 | they got this, what they call a hot spot,

01:15:56.480 | and in fact, that this heating had propagated

01:15:58.620 | out into the fuel, and that's the science

01:16:01.840 | behind inertial fusion.

01:16:02.920 | - So the idea behind a reactor that's based

01:16:05.240 | on this kind of inertial confinement

01:16:09.120 | is that you would have a new BB every like--

01:16:13.240 | - 10 times a second or something like that.

01:16:14.800 | - And that there's some kind of,

01:16:16.200 | so there's an incredible device that you kind of implied

01:16:19.720 | that kind of has to create one of those BBs.

01:16:22.140 | - So you have to make the BBs very fast.

01:16:24.820 | There's reports on this, but about what does it mean,

01:16:27.920 | the starting point is can you make this gain?

01:16:31.000 | So this was a scientific achievement, primarily.

01:16:33.880 | - Right, and the rest is just engineering.

01:16:35.640 | - No, no, no, the rest is incredibly

01:16:38.160 | complicated engineering.

01:16:39.360 | Well, in fact, there's still physics hurdles to overcome.

01:16:41.880 | So where does this come from?

01:16:43.800 | And it's actually because if you want to make

01:16:45.640 | an energy source out of this,

01:16:48.400 | this had a gain of around 1.5,

01:16:50.520 | that namely the fusion energy was approximately,

01:16:53.360 | was 1.5 times the laser input energy.

01:16:56.520 | Okay, this is a fairly significant threshold.

01:16:58.800 | However, from the science of what I just told you

01:17:01.960 | is that there's two fundamental efficiencies

01:17:04.420 | which come into it, which really come from physics, really.

01:17:06.960 | One of them is hydrodynamic efficiency.

01:17:09.060 | What I mean by this is that it's a rocket.

01:17:11.400 | So this just has a fundamental efficiency built into it,

01:17:16.440 | which comes out to orders of like 10%.

01:17:19.000 | So this means is that your ability to do work on the system

01:17:22.640 | is just limited by that, okay?

01:17:25.560 | And then the other one is the efficiency

01:17:26.920 | of laser systems themselves,

01:17:28.340 | which if the wall plug efficiency is 10%,

01:17:30.960 | you've done spectacularly well.

01:17:32.840 | In fact, the wall plug efficiency

01:17:34.680 | of the ones using that experiments are like more like 1%,

01:17:37.320 | right?

01:17:38.160 | So when you go through all of this,

01:17:39.800 | the approximate place that you're ordering this

01:17:42.920 | is for a fusion power plant would be a gain of 100,

01:17:46.720 | not 1.5.

01:17:48.120 | So you still, you know, and hopefully we see experiments

01:17:50.320 | that keep climbing up towards higher and higher gain,

01:17:53.940 | but then the whole fusion power plant

01:17:55.920 | is a totally different thing.

01:17:57.480 | So it's not one BB and one laser pulse per day.

01:18:02.480 | It's like 10 times, five or 10 times per second,

01:18:07.000 | like da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da-da

01:18:08.560 | like that, right?

01:18:09.400 | So you're doing it there.

01:18:11.040 | And then comes the other aspect.

01:18:13.520 | So it's making the targets, delivering them,

01:18:16.220 | being able to repeatedly get them to burn.

01:18:19.640 | And then we haven't even talked about like,

01:18:21.200 | how do you then get the fusion energy out?

01:18:23.520 | Which is mainly because these things

01:18:25.800 | are basically micro implosions, which are occurring.

01:18:29.260 | So this energy is coming out to some medium on the outside

01:18:33.040 | that you've got to figure out how to extract the energy

01:18:35.380 | out of this thing.

01:18:36.220 | - How do you convert that energy to electricity?

01:18:38.280 | - So in the end, you have to basically convert it

01:18:41.120 | into heat in some way.

01:18:42.200 | So most of the, in the end what fusion makes

01:18:45.520 | mostly is like very energetic particles

01:18:48.160 | from the fusion reaction.

01:18:49.560 | So you have to slow those down in some way

01:18:51.520 | and then make heat out of it.

01:18:53.960 | So basically the conversion of the kinetic energy

01:18:56.360 | of the particles into heating some engineered material

01:18:59.880 | that's on the outside of this.

01:19:01.320 | - And that's, from a physics perspective,

01:19:04.120 | is a somewhat solved problem, but from an engineering,

01:19:06.640 | is still-- - Yeah, yeah.

01:19:09.520 | Physics, I can draw the, I can show you all the equations

01:19:12.080 | that tell you about how it slows down

01:19:13.720 | and converts kinetic energy into heat.

01:19:16.600 | And then what that heat means, you know,

01:19:18.640 | you can write out like an ideal thermal cycle,

01:19:20.580 | like a Carnot cycle.

01:19:21.420 | So the physics of that, yeah, great.

01:19:23.000 | The integrated engineering of this is a whole other thing.

01:19:26.600 | - I'll ask you to maybe talk about the difference

01:19:28.400 | between inertial and magnetic,

01:19:30.520 | but first we'll talk about magnetic.

01:19:31.800 | But let me just linger on this breakthrough.

01:19:33.440 | You know, it's nice to have exciting things,

01:19:35.120 | but in a deep human sense,

01:19:38.200 | there's no competition in science and engineering.

01:19:40.480 | Or like you said, we're broad.

01:19:42.720 | First of all, we are humanity altogether.

01:19:45.160 | And you talk about this, it's a bunch of countries

01:19:46.960 | collaborating, it's really exciting.

01:19:49.480 | There's a nuclear fusion community broadly.

01:19:52.280 | But then there's also MIT.

01:19:53.800 | There's colors and logos, and it's exciting.

01:19:56.000 | And you have friends and colleagues here

01:19:59.560 | that work extremely hard and done some incredible stuff.

01:20:02.560 | Is there some sort of, how do you feel seeing somebody else

01:20:07.320 | get a breakthrough using a different technology?

01:20:09.880 | Is that exciting?

01:20:11.600 | Does the competitive fire get...

01:20:14.720 | (laughing)

01:20:15.680 | - All of the above.

01:20:16.680 | I mean, I have, so, you know,

01:20:20.680 | just to wave the flag a little bit.

01:20:23.080 | So MIT was a central player in this accomplishment.

01:20:28.000 | Interesting, I would say it showed our two,

01:20:31.080 | some of our two best traits.

01:20:32.360 | So one of them was that,

01:20:33.720 | like, how do you know that this happened?

01:20:36.960 | (laughing)

01:20:37.960 | This measurement, right?

01:20:39.160 | So one of the ways to do this is,

01:20:41.200 | if I told you is that in the DT fusion,

01:20:44.440 | what it actually, the product that comes out is helium,

01:20:48.000 | we call an alpha, but it's helium,

01:20:50.000 | and a free neutron, right?

01:20:52.200 | So the neutron contains 80% of the energy released

01:20:56.000 | by the fusion reaction.

01:20:57.400 | And it also, because it lacks a charge,

01:21:00.080 | it basically tends to just escape and go flying out.

01:21:02.680 | So this is what we would use eventually for,

01:21:05.680 | that's mostly what fusion energy would be.

01:21:07.520 | But so what my colleagues, my scientific colleagues

01:21:11.360 | at the Plaza Science and Fusion Center built

01:21:13.940 | were extraordinary measurement tools

01:21:15.840 | of being able to see the exact details

01:21:19.160 | of not only the number of neutrons that were coming out,

01:21:21.840 | but actually what energy that they're at.

01:21:24.320 | And by looking at that configuration,

01:21:26.640 | it reveals enormous, I'm not gonna scoop them

01:21:29.760 | because they need to publish the paper,

01:21:31.120 | but it reveals enormous amounts of scientific information

01:21:35.680 | about what's happening in that process

01:21:37.320 | that I just described.

01:21:38.400 | So exciting, I mean, and I have colleagues there

01:21:42.720 | that have worked for 30 years on this, for that moment.

01:21:46.160 | Of course you're excited for that, right?

01:21:48.240 | And it's one of those, there is nothing,

01:21:51.540 | it's hard to describe to people who aren't,

01:21:54.520 | it's almost addicting to be a scientist

01:21:57.260 | when you get to be at the forefront of research of anything.

01:22:00.300 | Like when you see like an actual discovery of some kind

01:22:04.140 | and you're looking at it,

01:22:04.980 | particularly when you're the person who did it, right?

01:22:07.180 | And you go, no human being has ever seen this

01:22:09.620 | or understood this, it's like, it's pretty thrilling, right?

01:22:12.980 | So even in proxy, it's incredibly thrilling to see this.

01:22:17.680 | It's not, I don't wanna say it's rivalry or jealousy,

01:22:20.660 | it's like, I can tell you already, fusion is really hard.

01:22:23.860 | So anything that keeps pushing the needle forward

01:22:26.580 | is a good thing, but we also have to be realistic

01:22:28.820 | about what it means to making a fusion energy system.

01:22:31.900 | That's the--

01:22:32.740 | - And then, but that's the, I mean,

01:22:34.260 | these are still the early steps,

01:22:37.340 | maybe you can say the early leaps.

01:22:39.060 | So let's talk about the magnetic confinement.

01:22:42.560 | What is, how does magnetic confinement work?

01:22:46.860 | What's the tokamak?

01:22:47.920 | Yeah, how does it all work?

01:22:50.140 | - So go back to that.

01:22:50.980 | So why inertial confinement works on the same principle

01:22:53.620 | that a star works.

01:22:55.520 | So like, what is the confinement mechanism in the star

01:22:58.900 | is gravity, because it's its own inertia

01:23:03.900 | of the something the size of the sun

01:23:06.620 | basically pushes literally a force by gravity

01:23:09.860 | against the center.

01:23:11.160 | So the center is very, very hot, 20 million degrees,

01:23:14.780 | and literally outside the sun, it's essentially zero

01:23:16.940 | 'cause it's a vacuum of space.

01:23:18.740 | How the hell does that do that?

01:23:20.140 | It does that by, and it's out of,

01:23:22.820 | like, why doesn't it just leak all of its heat?

01:23:24.580 | It doesn't leak its heat because it all is held together

01:23:27.540 | by the fact that it can't escape because of its own gravity.

01:23:30.340 | So this is why the fusion happens in the center of the star.

01:23:33.060 | Like we think of the surface of the sun as being hot.

01:23:35.180 | That's the coldest part of the star.

01:23:37.060 | So if our own sun, this is about 5,500 degrees,

01:23:39.540 | a beautiful symmetry, by the way, it's like,

01:23:41.400 | so how do we know all this?

01:23:42.580 | 'Cause we can't of course see directly

01:23:45.060 | into the interior of the sun,

01:23:47.060 | but by knowing the volume and the temperature

01:23:49.120 | of the surface of the sun,

01:23:50.160 | you know exactly how much power it's putting out.

01:23:52.300 | And by this, you know that this is coming

01:23:54.380 | from fusion reactions occurring at exactly the same rate

01:23:57.940 | in the middle of the sun.

01:24:00.260 | - Is it possible as a small tangent

01:24:02.540 | to build an inertial confinement system like the sun?

01:24:07.540 | Is it possible to create a sun?

01:24:09.380 | - It is of course possible to make a sun,

01:24:11.140 | although we do have stars, but it is not impossible on Earth

01:24:14.540 | because for the simple reason that it takes,

01:24:17.280 | the gravitational force is extremely weak.

01:24:19.560 | And so it takes something like the size of a star

01:24:22.540 | to make fusion occur in the center.

01:24:24.180 | - Well, I didn't mean on Earth.

01:24:26.020 | I mean, if you had to build like a second sun,

01:24:28.820 | how would you do it?

01:24:29.660 | - You can't, there's not enough hydrogen around.

01:24:32.320 | - So the limiting factor is just the hydrogen.

01:24:35.860 | - Yeah, I mean, the forces and energy that it takes

01:24:38.940 | to assemble that is just mind boggling.

01:24:41.760 | (laughing)

01:24:42.860 | - All right. - So we wouldn't do that.

01:24:43.700 | - To be continued. - Yeah, to be continued.

01:24:45.420 | So what are we doing it with?

01:24:46.560 | So in the one that I just described,

01:24:48.020 | it's like you say, so you have to replace this

01:24:49.740 | with some force which is better than that.

01:24:52.620 | And so what I mean by that is it's stronger than that.

01:24:56.180 | So what I talked about the laser fusion,

01:24:58.540 | this is coming from the force,

01:24:59.900 | which is enormous compared to gravity,

01:25:01.820 | like from the rocket action of pushing it together.

01:25:05.300 | So in magnetic confinement, we use another force of nature,

01:25:08.920 | which is the electromagnetic force.

01:25:11.100 | And that's very, it's orders and orders of magnitude

01:25:14.520 | stronger than the gravitational force.

01:25:17.620 | And the key force that matters here

01:25:19.340 | is that if you have a charged particle,

01:25:21.340 | that namely it's a particle that has an electric,

01:25:23.500 | net electric charge,

01:25:25.180 | and it's in the proximity of a magnetic field,

01:25:28.060 | then there is a force which is exerted on that particle.

01:25:31.660 | So it's called the Lorentz force

01:25:33.980 | for those who are keeping track.

01:25:35.680 | So that is the force that we use

01:25:38.060 | to replace physical containment.

01:25:40.620 | So this again, how do you hold something

01:25:44.380 | at a hundred million degrees?

01:25:45.860 | It's impossible in a physical container.

01:25:48.380 | This is not like, you know,

01:25:49.780 | it's not this plastic bottle holding in this liquid

01:25:52.540 | or a gas chamber.

01:25:54.380 | What you're doing is you're using,

01:25:56.300 | you're immersing the fuel in a magnetic field

01:25:59.480 | that basically exerts a force at a distance.

01:26:02.380 | This comes back again to again,

01:26:03.860 | like why plazas are so strange.

01:26:05.820 | It's the same thing here.

01:26:07.020 | And if it's immersed in this magnetic field,

01:26:08.820 | you're not actually physically touching it,

01:26:10.940 | but you're making a force go onto it.

01:26:13.240 | So that's the inherent feature of magnetic confinement.

01:26:18.240 | And then magnetic confinement devices are like a tokamak,

01:26:21.620 | are basically configurations which exploit the features

01:26:25.780 | of that magnetic containment.

01:26:27.740 | There's several features to it.

01:26:28.820 | One is that the stronger the strength

01:26:30.980 | of the magnetic field, the stronger the force.

01:26:33.260 | And for this reason is that if you increase the strength

01:26:36.980 | of magnetic fields, this means that the containment,

01:26:40.460 | because namely the force which you're pushing against it

01:26:42.380 | is more effective.

01:26:44.140 | And the other feature is that there is no force.

01:26:48.020 | So for those who remember magnetic fields,

01:26:50.100 | what are these things?

01:26:51.060 | They're also invisible.

01:26:52.620 | But if you think of a permanent magnets

01:26:54.700 | or your fridge magnet, there are field lines,

01:26:57.480 | which we actually designate as arrows,

01:26:59.180 | which are going around.

01:27:00.000 | You sometimes see this in school when you have

01:27:02.380 | the iron filings on a thing and you see the directions

01:27:06.040 | of the magnetic field lines, or when you use a compass.

01:27:09.580 | So that's telling you,

01:27:11.220 | because we're living in an immersed magnetic field

01:27:13.900 | made by the earth, which is at very low intensity,

01:27:16.620 | but it's strong enough that we can actually see

01:27:18.460 | what direction is it.

01:27:19.460 | So this is the arrow that the magnetic field is pointing.

01:27:22.260 | It's always pointing north and for us.

01:27:24.220 | So an interesting feature of this force

01:27:27.180 | is that there is no force along the direction

01:27:29.500 | of the magnetic field.

01:27:31.060 | There's only force in the directions orthogonal

01:27:33.320 | to the magnetic field.

01:27:34.820 | So this, by the way, is a huge deal

01:27:36.980 | in a whole other discipline of plasma physics,

01:27:40.880 | which is like the study of our near atmosphere.

01:27:44.200 | So the study of aurora borealis,

01:27:46.320 | what's happening in the near atmosphere,

01:27:47.860 | what happens when solar flares hit the magnetic field.

01:27:50.020 | In fact, remember I said fusion is the reason

01:27:53.960 | that life is responsible in the universe?

01:27:57.020 | Well, you could also argue so is magnetic confinement

01:27:59.500 | because the charged particles which are being emitted

01:28:03.340 | from the galaxy and from our own star

01:28:06.860 | would be very, very damaging on earth.

01:28:09.820 | So we get two layers of protection.

01:28:11.900 | One is the atmosphere itself,

01:28:13.740 | but the other one is the magnetic field

01:28:15.540 | which surrounds the earth and basically traps

01:28:17.940 | these charged particles so they can't get away.

01:28:19.740 | It's the same deal.

01:28:21.860 | - How do you create a strong magnetic field?

01:28:23.700 | - Yeah, so--

01:28:25.700 | - With a giant magnet.

01:28:26.780 | - Giant magnet, yeah.

01:28:28.060 | So it's basically true.

01:28:30.620 | - Engineering is awesome.

01:28:31.460 | - There's essentially two ways to create a magnet.

01:28:33.940 | So one of them is that we're familiar with

01:28:35.900 | like fridge magnets and so forth.

01:28:37.220 | These are so-called permanent magnets.

01:28:39.180 | And what it means is that within these,

01:28:41.300 | the atoms arrange in a particular way

01:28:42.980 | that it produces the electrons basically

01:28:45.100 | arranged in a particular way that it produces

01:28:47.340 | a permanent magnetic field that is set by the material.

01:28:50.460 | So those have a fundamental limitation

01:28:53.620 | how strong they can be and they also tend to have

01:28:55.860 | this like circular shape like this.

01:28:58.420 | So we don't typically use those.

01:29:01.060 | So what we use are so-called electromagnets.

01:29:03.340 | And what is this?

01:29:04.180 | It's like, so the other way to make a magnetic field

01:29:06.940 | also go back to your elementary school physics

01:29:11.220 | or science class is that you take a nail

01:29:14.380 | and you wrap a copper wire around it

01:29:16.020 | and connect it to a battery,

01:29:17.020 | then it can pick up iron filings.

01:29:18.860 | This is an electromagnet.

01:29:20.100 | And it's simplest what it is, it's an electric current

01:29:23.700 | which is going in a pattern around and around and around.

01:29:27.020 | And what this does is it produces a magnetic field

01:29:29.420 | which goes through it by the laws of electromagnetism.

01:29:32.580 | So that's what an electric,

01:29:34.500 | so that's how we make the magnetic field

01:29:36.620 | in these configurations.

01:29:39.060 | And the key there is that it's not limited

01:29:42.580 | by the magnetic property of the material.

01:29:45.460 | The magnetic field amplitude is set by the amount of,

01:29:48.820 | the geometry of this thing and the amount of electric

01:29:51.660 | current that you're putting through.

01:29:53.100 | And the more electric current that you put through,

01:29:55.500 | the more magnetic field that you get.

01:29:57.500 | The closest one that people maybe see is

01:30:01.940 | one of my favorite skits actually was Super Dave Osborne

01:30:06.940 | on, it's probably past years,

01:30:09.540 | like in a show called Bizarre.

01:30:10.820 | Super Dave Osborne, which is a great comedian called,

01:30:13.820 | he was a stunt man and one of his tricks was that he was,

01:30:16.700 | he gets into a car and then one of those things

01:30:18.660 | in the junkyard comes down,

01:30:20.540 | and picks up the car and then puts it into the crusher.

01:30:23.460 | This is his stunt, which is pretty hilarious.

01:30:25.540 | Anyway, but that thing that picks him up,

01:30:28.540 | like how does that work?

01:30:29.620 | That's actually not a permanent magnet,

01:30:31.100 | it's an electromagnet.

01:30:33.140 | And so you can turn, by turning off and on the power supply,

01:30:36.260 | it turns off and on the magnetic field.

01:30:38.380 | So this means you can pick it up and then when you switch

01:30:40.820 | it off, the magnetic field goes away and the car drops.

01:30:43.780 | Okay, so that's what it looks like.

01:30:46.420 | - Speaking of giant magnets, MIT and Commonwealth Fusion

01:30:50.580 | Systems, CFS, built a very large, high temperature,

01:30:55.540 | superconducting electromagnet that was ramped up

01:30:58.980 | to a field strength of 20 Tesla,

01:31:01.140 | the most powerful magnetic field of its kind

01:31:03.300 | ever created on Earth.

01:31:04.720 | Because I enjoy this kind of thing,

01:31:07.740 | can you please tell me about this magnet?

01:31:09.300 | - Yeah, sure.

01:31:10.740 | Oh, it was, it's fun, yeah.

01:31:12.900 | There's a lot to parse there.

01:31:14.140 | So maybe, so we already explained an electromagnet,

01:31:18.420 | which in general is, what you do is you take electric

01:31:22.560 | current and you force it to follow a pattern of some kind,

01:31:25.940 | typically like a circular pattern,

01:31:27.820 | around and around and around and around.

01:31:29.580 | It goes, the more time, the more current and the more times

01:31:31.780 | it goes around, the stronger the magnetic field

01:31:33.580 | that you make of it.

01:31:35.380 | And as I pointed out, it's like really important

01:31:37.780 | in magnetic confinement because it is the force

01:31:40.820 | that's produced by that magnet.

01:31:41.900 | In fact, technically it goes like the magnetic field

01:31:44.400 | squared because it's a pressure which is actually

01:31:47.740 | being exerted on the plasma to keep it contained.

01:31:52.580 | - Just so we know, for magnetic confinement,

01:31:54.940 | what is usually the geometry of the magnet?

01:31:57.220 | What are we supposed to imagine?

01:31:58.820 | - Yeah, so the geometry is typically that,

01:32:01.260 | typically is what you do is you want to produce

01:32:04.380 | a magnetic field that loops back on itself.

01:32:07.300 | And the reason for this was, goes down to the nature

01:32:10.920 | of the force that I described, which is that there's no,

01:32:15.440 | there's no containment or force along the direction

01:32:18.540 | of the magnetic field.

01:32:19.980 | So here's a magnetic field.

01:32:21.380 | In fact, what it's more technically or more graphically

01:32:25.340 | what it's doing is that when the plasma is here,

01:32:28.140 | here's plasma particles here, here's a magnetic field.

01:32:31.260 | What it does is it forces all those,

01:32:33.260 | because of this Lorentz force, it makes all of those

01:32:37.100 | charged particles execute circular orbits

01:32:39.500 | around the magnetic field.

01:32:41.460 | And they go around like this.

01:32:42.980 | But they stream freely along the magnetic field line.

01:32:46.500 | So this is why the nature of the containment

01:32:49.100 | is that if you can get that circle smaller and smaller,

01:32:51.700 | it stays further away from Earth, temperature materials.

01:32:56.020 | That's why the confinement gets better.

01:32:57.860 | But the problem is is that because it free streams along,

01:33:00.520 | so we just have a long straight magnetic field,

01:33:03.340 | okay, it'll just keep leaking out the ends like really fast.

01:33:06.660 | So you get rid of the ends.

01:33:07.940 | So you basically loop it back around.

01:33:10.480 | So what these look like are typically donut shaped

01:33:13.260 | or more technically toroidal shape,

01:33:15.580 | but donut shaped things where this collection

01:33:19.760 | of magnetic fields loops back on itself.

01:33:21.920 | And it also, for reasons which are more complicated

01:33:24.420 | to explain, basically it also twists slowly around

01:33:28.640 | in this direction as well too.

01:33:30.480 | So that's what it looks like.

01:33:31.960 | That's what the plasma looks like,

01:33:33.520 | because that's what the fuel looks like.

01:33:35.320 | So then this means is that the electromagnets

01:33:39.340 | are configured in such a way that it produces

01:33:41.680 | the desired magnetic fields around this.

01:33:44.160 | - How precise does this have to be?

01:33:45.800 | - You were probably listening to our conversation

01:33:47.840 | with some of my colleagues yesterday.

01:33:49.400 | So it's actually, it depends on the configuration

01:33:52.480 | about how you're doing it.

01:33:54.240 | - The configuration of the plasma, sorry.

01:33:55.280 | - The configuration of the electromagnets

01:33:57.120 | and about how you're achieving this requirement.

01:33:59.520 | It's fairly precise, but it doesn't have to be,

01:34:04.980 | particularly in something like a tokamak,

01:34:06.520 | what we do is we produce planar coils,

01:34:08.960 | which just mean they're flat, and we situate them.

01:34:12.000 | So if you think of a circle like this,

01:34:15.680 | what does it produce if you put current through it?

01:34:17.680 | It produces a magnetic field which goes

01:34:19.640 | through the circle like this.

01:34:21.720 | So if you align many of them like this, this, this, this,

01:34:25.640 | there's things on line, you can go see the picture.

01:34:28.800 | You keep arranging these around in a circle itself,

01:34:31.600 | this forces the magnetic field lines

01:34:33.200 | to basically just keep executing around like this.

01:34:35.600 | So you tend to align.

01:34:36.800 | That one tends to, well, it requires good alignment.

01:34:41.520 | It's not like insane alignment,

01:34:43.320 | because you're actually exploiting the symmetry

01:34:46.120 | of the situation to help it.

01:34:48.200 | There's another kind of configuration of magnetic,

01:34:50.600 | of this kind of magnetic confinement called a stellarator,

01:34:53.000 | which is, we have these names for historic reasons.

01:34:56.800 | - Which is different than a tokamak.

01:34:58.080 | - It's different than a tokamak,

01:34:58.920 | but actually works on the same physical principle,

01:35:00.960 | that namely, in the end it produces a plasma

01:35:03.240 | which loops in magnetic fields,

01:35:05.000 | which loop back on themselves as well.

01:35:07.400 | But in that case, the totality, basically,

01:35:10.800 | the totality of the confining magnetic field

01:35:12.840 | is produced by external three-dimensional magnets,

01:35:16.200 | so they're twisted.

01:35:17.200 | And it turns out the precision of those is more stringent.

01:35:23.080 | - So are tokamaks by far more popular

01:35:25.840 | for research and development currently than stellarators?

01:35:29.280 | - Of the concepts which are there,

01:35:30.720 | the tokamak is by far the most mature

01:35:33.280 | in terms of its breadth of performance

01:35:36.120 | and thinking about how it would be applied

01:35:40.000 | in a fusion energy system.

01:35:41.640 | And the history of this was that many,

01:35:43.360 | in fact, you asked, if we go back to the history

01:35:45.520 | of the Plasma Science and Fusion Center,

01:35:47.400 | the history of fusion is that people,

01:35:50.600 | scientists had started to work on this in the 1950s.

01:35:53.440 | It was all hush-hush and Cold War and all that kind of stuff.

01:35:57.080 | And it's like, they realized, holy cow,

01:35:59.400 | this is like really hard.

01:36:01.200 | Like, we actually don't really know what we're doing

01:36:03.720 | in this, 'cause everything was at low temperatures,

01:36:06.400 | they couldn't get confinement.

01:36:08.240 | It was interesting.

01:36:09.080 | And then they declassified it,

01:36:10.920 | and this is one of the few places

01:36:13.520 | that the West and the Soviet Union

01:36:15.960 | actually collaborated on was the science of this.

01:36:17.920 | - Even during the Cold War.

01:36:18.760 | - Even during the middle of the Cold War, it was really,

01:36:21.320 | and this actually perpetuates all the way till now,

01:36:24.080 | for we can talk about the project

01:36:26.800 | that that is sort of captured in now.

01:36:29.640 | But, and the reason they declassified it

01:36:34.600 | is because everything kind of sucked, basically,

01:36:38.920 | about trying to make this confinement

01:36:40.840 | in high-temperature plasma.

01:36:42.760 | And then the Russians, then the Soviets,

01:36:46.000 | came along with this device called a TOKAMAK,

01:36:48.760 | which is a Russian acronym, which basically means

01:36:51.560 | magnetic coils arranged in the shape of a donut.

01:36:56.040 | And they said, holy cow, like everyone was stuck

01:37:01.040 | at like a meager, like half a million degrees,

01:37:04.840 | or half a million degrees, which is like infusion

01:37:07.920 | in terms of zero, basically.

01:37:09.720 | And then they come along and they say,

01:37:11.320 | oh, we've actually achieved a temperature

01:37:13.080 | 20 times higher than everybody else.

01:37:15.440 | And it's actually started to make fusion reactions,

01:37:17.320 | and everyone just go, oh, no way, it's just hype.

01:37:21.080 | It's like, there's no way, 'cause we've failed at this.

01:37:23.840 | It's a great story in the history of fusion,

01:37:26.800 | is that then, but they insisted, they said,

01:37:28.520 | no, look, you can see this from our data.

01:37:30.160 | It's like, this thing is really hot,

01:37:32.080 | and it seems to be working.

01:37:33.080 | This is late 1960s.

01:37:35.320 | And there was a team that went from the United Kingdom's

01:37:40.000 | fusion development lab, and they brought this very fancy,

01:37:43.640 | amazing new technology called a laser.

01:37:46.360 | And they used this laser, and they shot the laser beam

01:37:51.160 | like through the plasma, and by looking at the scattered

01:37:53.960 | light that came from it, they go, basically,

01:37:56.920 | the scattered light gets more broadened in its spectrum

01:38:00.240 | if it gets hotter.

01:38:01.360 | So you could exactly tell the temperature of this,

01:38:03.920 | and even though you're not physically touching the plasma,

01:38:06.080 | it's like, holy cow, you're right, it is.

01:38:08.880 | It is 10 million degrees.

01:38:10.400 | And so this was one of those explosions of everyone

01:38:15.400 | in the world then wanted to build a token back,

01:38:18.240 | because it was clearly like, wow, this is so far ahead

01:38:22.680 | of everything else that we tried before.

01:38:25.480 | So that actually has a part of the story to MIT

01:38:27.840 | and the Plasma Science and Fusion Center was,

01:38:30.400 | why is there a strong fusion and a major fusion program

01:38:34.160 | at MIT?

01:38:35.160 | It was because we were host to the Francis Bitter

01:38:38.360 | Magnet Laboratory, which is also the National High Field

01:38:40.960 | Magnet Laboratory.

01:38:42.480 | Well, you can see where this goes, right?

01:38:44.080 | From this, you know, we're kind of telling the stories

01:38:46.280 | backwards almost, but, you know, the advent of a tokamak,

01:38:51.280 | along with the fact that you could make very strong

01:38:55.280 | magnetic fields with the technology that had been

01:38:57.400 | developed with that laboratory, that was the origins

01:39:00.040 | of sort of pushing together the physics of the plasma

01:39:03.520 | containment and the magnet technology and put them together

01:39:07.520 | in a way that I would say is, you know, a very typical

01:39:09.920 | MIT success story, right?

01:39:11.480 | We don't do just pure science or pure technology,

01:39:14.680 | we sort of set up this intersection between them.

01:39:16.560 | And there were several pioneers of people at MIT,

01:39:21.480 | like Bruno Coppi, who's a professor in the physics

01:39:23.520 | department and Ron Parker, who was a professor

01:39:26.240 | in electrical engineering and nuclear engineering.

01:39:28.320 | It's like even the makeup of the people, right,

01:39:30.200 | has got this blends of science and engineering in them.

01:39:33.080 | And that's actually was the origin of the Plasma Science

01:39:35.080 | and Fusion Center was doing those things.

01:39:36.960 | So anyway, so back to this.

01:39:38.240 | So why, so yes, tokamaks have been, have achieved

01:39:41.880 | the highest in magnetic fusion by far, like the best

01:39:45.760 | amounts of these conditions that I talked about.

01:39:48.920 | And in fact, pushed right up to the point where they were

01:39:51.840 | near QP of one, they just didn't quite get over one.

01:39:56.000 | - So can we actually just linger on the collaboration

01:39:59.400 | across different nations, just maybe looking at

01:40:02.460 | the philosophical aspect of this.

01:40:04.100 | Even in the Cold War, there's something hopeful to me

01:40:10.440 | besides the energy, that these giant international projects

01:40:14.400 | are a really powerful way to ease some of the geopolitical

01:40:19.740 | tension, even military conflict across nations.

01:40:23.080 | There's a war in Ukraine and Russia.

01:40:28.080 | There's a brewing tension and conflict with China.

01:40:33.080 | Just the world is still seeking military conflict,

01:40:38.080 | cold or hot.

01:40:39.860 | What can you say about sort of the lessons of the 20th

01:40:43.640 | century and these giant projects and their ability

01:40:46.660 | to ease some of this tension?

01:40:48.800 | - So it's a great question.

01:40:50.460 | So as I said, there was a reason, because it was so hard,

01:40:53.380 | that was one of the reasons they declassified it.

01:40:57.060 | And actually they started working together in some sense

01:40:59.740 | on it as well too.

01:41:01.300 | And I think it was really, there was a heuristic

01:41:04.300 | or altruistic aspect to this.

01:41:11.080 | It's like, this is something that could change the future

01:41:15.700 | of humanity and its nature and its relationship with energy.

01:41:19.040 | Isn't this something that we should work on together?

01:41:21.740 | Right, and that went along in those ones.

01:41:25.260 | And in particularly that any kind of place where you can

01:41:28.940 | actually have an open exchange of people who are sort of

01:41:33.260 | at the intellectual frontiers of your society,

01:41:36.060 | this is a good thing, right?

01:41:37.500 | Of being able to collaborate.

01:41:39.180 | I've had the, I mean, I have had an amazing career.

01:41:43.780 | I've worked with people from, it's like hard to throw a dart

01:41:47.180 | at a country on the map and not hit a country of people

01:41:50.280 | that I've been able to work with.

01:41:51.520 | How amazing is that?

01:41:53.320 | And even just getting small numbers of people to bridge

01:41:56.840 | the cultural and societal divides is a very important thing.

01:42:01.840 | Even when it's a very teeny fraction

01:42:05.680 | of the overall populations, it can be held up

01:42:08.280 | as an example of that.

01:42:10.400 | But it's interesting that if you look at then

01:42:13.480 | that continued collaboration, which continues to this day,

01:42:16.960 | is that this actually played a major role, in fact,

01:42:20.460 | in East-West relations, or like Soviet-West relations,

01:42:24.700 | is that back in the Reagan-Gorbachev days,

01:42:29.160 | which of course were interesting in themselves

01:42:31.020 | of all kinds of changes happening on both sides, right?

01:42:36.020 | But still, like a desire to push down the stockpile

01:42:41.140 | of nuclear weapons and all that, within that context,

01:42:44.540 | there was a fairly significant historic event

01:42:48.700 | that at one of the Reagan-Gorbachev summits

01:42:52.600 | is that they had really, they didn't get there.

01:42:54.900 | Like they couldn't figure out how to bargain

01:42:57.180 | to the point of some part of the treaty,

01:42:59.940 | I can't remember the details of it anymore.

01:43:02.100 | But they needed some kind of a symbol, almost, to say,

01:43:06.540 | but we're still gonna keep working towards something

01:43:09.420 | that's important for all of us.

01:43:11.020 | What did they pick?

01:43:11.840 | A fusion project.

01:43:14.380 | And that was in the mid-1980s, and actually,

01:43:18.340 | then after, so they basically signed an agreement

01:43:21.780 | that they would move forward to like literally collaborate

01:43:24.340 | on a project whose idea would be to show

01:43:27.540 | large net energy gain in fusions, commercial viability,

01:43:31.540 | and work together on that.

01:43:33.100 | And very soon after that, Japan joined,

01:43:35.340 | as did the European Union.

01:43:37.180 | And now, that project, it evolved

01:43:41.940 | over a long period of time,

01:43:43.020 | it had some interesting political ramifications to it,

01:43:45.700 | but in the end, this actually also had South Korea,

01:43:49.620 | India, and China join as well, too.

01:43:53.140 | So you're talking about a major fraction of,

01:43:58.140 | and now Russia, of course, instead of the Soviet Union.

01:44:01.860 | And actually, that coalition is holding together

01:44:04.000 | despite the obvious political turmoil

01:44:07.520 | that's going around on all those things.

01:44:09.280 | And that's a project called ITER,

01:44:11.160 | which is under construction in the south of France

01:44:13.700 | right now.

01:44:14.540 | - Can you actually, before we turn to the giant magnet,

01:44:16.940 | and maybe even talk about Spark,

01:44:18.380 | and the stuff going, all amazing stuff going on at MIT,

01:44:21.940 | what is ITER?

01:44:22.780 | What is this international nuclear fusion mega project

01:44:26.300 | being built in the south of France?

01:44:28.780 | - So its scientific purpose is a worthy one

01:44:31.380 | that it's essentially, in any fusion device,

01:44:34.340 | the thing that you want to see is more and more

01:44:36.540 | relative amounts of self-heating.

01:44:38.540 | And this is something that had not been seen,

01:44:40.700 | although we had made fusion reactions,

01:44:42.640 | and we'd seen small amounts of the self-heating,

01:44:45.420 | we never got to a dominant,

01:44:46.640 | this actually goes to this QP business, okay?

01:44:49.420 | The goal of ITER,

01:44:51.380 | and it shifted around a little bit historically,

01:44:53.080 | but fairly quickly became,

01:44:55.020 | we want to get to a large amount of self-heating.

01:44:57.740 | So this is why it has,

01:44:59.700 | its primary feature is to get to QP of around 10,

01:45:03.480 | and through this, this is a way to study this plasma

01:45:07.360 | that has more higher levels of self-determination

01:45:10.740 | around on it.

01:45:12.420 | But it also has another feature,

01:45:14.400 | which was let's produce fusion power at a relevant scale.

01:45:19.400 | And actually they're linked together,

01:45:21.720 | which actually makes sense when you think about it,

01:45:23.220 | is that because the fusion power

01:45:25.640 | is the heating source itself,

01:45:27.480 | this means that they're linked together.

01:45:29.360 | And so ITER is projected to make

01:45:32.660 | about 500 million watts of fusion power.

01:45:36.760 | So this is a significant amount,

01:45:38.460 | like this is what you would use for powering cities.

01:45:41.860 | - So it's not just the research,

01:45:43.980 | it is the development of really trying to achieve scale here,

01:45:46.460 | so self-heating and scale.

01:45:48.340 | - Yeah, yes.

01:45:49.740 | So this meant then too is the development

01:45:53.840 | of an industrial base

01:45:55.380 | that can actually produce the technologies

01:45:57.100 | like the electromagnets and so forth.

01:45:59.100 | And to do it with, it is a tokamak,

01:46:00.860 | it is one of these, yes.

01:46:02.940 | But very interesting,

01:46:03.780 | it also revealed limitations of this as well too.

01:46:06.920 | - Like what?

01:46:07.760 | - Well, it's interesting is that it is clearly on paper,

01:46:12.520 | and in fact, in practice as well too,

01:46:16.640 | the world, and very different political systems,

01:46:20.920 | and you consider at least geopolitical or economic rivals

01:46:25.160 | or whatever you want to use.

01:46:26.520 | Like working towards a common cause,

01:46:29.480 | and one that we all think is worthy,

01:46:31.400 | is very like, okay, that's very satisfying.

01:46:34.580 | But it's also interesting to see the limitations of this,

01:46:37.760 | it's because, well, you've got seven chefs in the kitchen.

01:46:41.880 | So what does this mean in terms of the speed of the project

01:46:47.780 | and the ability to govern it and so forth?

01:46:50.180 | It's just been a challenge, honestly, around this.

01:46:52.900 | And this is, I mean, it's very hard technically

01:46:56.060 | what's occurring, but when you also introduce such levels,

01:47:00.060 | I mean, this isn't just me saying it,

01:47:01.660 | there's like GAO reports from the US government

01:47:03.940 | and so forth, it's hard to like steer all of this around.

01:47:07.740 | And what that's tended to do is make it,

01:47:11.540 | it's not the fastest decision-making process.

01:47:15.140 | My own personal view of it was, it was interesting

01:47:17.820 | 'cause you asked, you said about the magnet

01:47:19.420 | and commonwealth fusion systems.

01:47:21.620 | It was, I worked most of my career on ITER,

01:47:25.580 | because when I came into the field in the early 1990s,

01:47:28.940 | when I completed my PhD and started to work,

01:47:32.380 | this was one of the most, like you can't imagine

01:47:34.700 | being more excited about something,

01:47:36.340 | like we're going to change the world with this project,

01:47:38.620 | we're gonna do these things.

01:47:39.900 | And we just like poured like an entire generation,

01:47:43.300 | and afterwards as well too, just poured their imagination

01:47:46.380 | and their creativity about making this thing work.

01:47:48.900 | Very good.

01:47:49.740 | But also at some point though, when it got to being

01:47:54.260 | another five years of delay or a decade of delay,

01:47:56.980 | you start asking yourself, well, is this what I want to do?

01:48:00.860 | Right, am I going to wait for this?

01:48:02.620 | So it was a part of me starting to ask questions

01:48:05.620 | with my students, I was like, is there another way

01:48:10.180 | that we can get to this extremely worthwhile goal

01:48:13.020 | that maybe it's not that pathway?

01:48:16.940 | And the other part that was clearly frustrating to me,

01:48:19.380 | 'cause I'm an advocate of fusion.

01:48:21.860 | You asked me about, was I, I was like,

01:48:23.940 | well, it's laser fusion or inertial fusion

01:48:27.140 | or magnetic fusion.

01:48:28.260 | I just want fusion energy, okay?

01:48:30.180 | 'Cause I think it's so important to the world is that,

01:48:33.860 | but the other thing, if that's the case,

01:48:36.420 | then why do we have only one attempt at it

01:48:41.620 | on the entire planet, which was ITERF?

01:48:44.020 | It's like, that makes no sense to me, right?

01:48:47.900 | We should have multiple attempts at this

01:48:50.240 | with different levels of whatever you want to think about it.

01:48:54.320 | Technical, schedule, scientific risk,

01:48:56.640 | which are incorporated in them,

01:48:57.960 | and that's going to give us a better chance

01:48:59.400 | of actually getting to the goal line.

01:49:01.240 | - With that spirit, you're leading MIT's effort

01:49:03.680 | to design SPARC, a compact, high-field,

01:49:07.160 | DT-burning tokamak.

01:49:09.640 | How does it work?

01:49:10.720 | What is it, what's the motivation?

01:49:13.120 | What's the design, what are the ideas behind it?

01:49:14.960 | - Yeah, at its heart, it's exactly the same concept as ITER.

01:49:18.800 | So it's basically a configuration of electromagnets.

01:49:22.200 | It's arranged in the shape of a donut,

01:49:24.360 | and within that, we would do the same thing

01:49:26.840 | that happens in all the other tokamaks,

01:49:28.960 | and including in ITER and in this one,

01:49:30.920 | is that namely, you put in gas,

01:49:32.360 | make it into a plasma, you heat it up,

01:49:34.640 | it gets to about 100 million degrees.

01:49:37.040 | The differentiator in SPARC is that

01:49:40.020 | we use the actual deuterium-tritium fuel,

01:49:43.040 | and because of the access to very high magnetic fields,

01:49:48.200 | it's in a very compact space.

01:49:51.040 | It's very, very small.

01:49:53.960 | What do I mean by small?

01:49:55.280 | So it's 40 times smaller in volume than ITER,

01:49:59.280 | but it uses exactly the same physical principles.

01:50:02.880 | So this comes from the high magnetic field.

01:50:05.040 | So in the end, like, why does this matter?

01:50:07.360 | What it does is it does those things,

01:50:09.680 | and it should get to the point where it's producing

01:50:12.080 | over 100 million watts of fusion power,

01:50:15.040 | but remember, it's 40 times smaller.

01:50:17.840 | So ITER was 500 megawatts.

01:50:19.880 | Technically, our design is around 150 megawatts,

01:50:23.640 | so it's only about a factor of three difference,

01:50:25.360 | despite being 40 times smaller.

01:50:27.380 | And we see QP large,

01:50:32.500 | order of 10 or something like this.

01:50:35.280 | At that state, it's very important scientifically,

01:50:39.020 | because this basically matches what ITER is looking to do.

01:50:42.680 | The plasma's dominated by its own heating.

01:50:45.480 | That's very, very important.

01:50:47.400 | And it does that for about 10 seconds.

01:50:49.480 | And the reason it's for 10 seconds is that in terms of,

01:50:53.680 | that basically allows everything to settle

01:50:55.960 | in terms of the fusion in the plasma equilibrium.

01:50:59.240 | Everything is nice and settled.

01:51:01.200 | So you know, you have seen the physical state

01:51:04.240 | at which you would expect a power plant to operate

01:51:07.040 | basically for magnetic fusion.

01:51:09.360 | Like, wow, right?

01:51:11.360 | But it's more than that.

01:51:13.240 | And it's more than that, it's because about

01:51:15.200 | who's building it and why and how it's being financed.

01:51:18.420 | So that scientific pathway was made possible

01:51:22.920 | by the fact that we had access to a next generation

01:51:26.300 | of magnet technology.

01:51:28.540 | So to explain this real quick, why do we call it,

01:51:30.660 | you said it in the words, a superconducting magnet.

01:51:33.400 | What does this mean?

01:51:34.760 | Superconducting magnet means that the materials

01:51:36.840 | which are in the electromagnet

01:51:38.540 | have no electrical resistance.

01:51:40.420 | Therefore, when the electric current is put into it,

01:51:44.080 | the current goes around unimpeded.

01:51:46.400 | So it could basically keep going around and around,

01:51:48.520 | you know, technically for infinity.

01:51:50.320 | And what that means, or for eternity.

01:51:52.080 | And what that means is that when you energize

01:51:55.820 | these large electromagnets, they're using basically

01:51:58.800 | zero electrical power to maintain them.

01:52:01.580 | Whereas if you would do this in a normal wire, like copper,

01:52:05.840 | you basically make an enormous toaster oven

01:52:08.240 | that's consuming enormous amounts of power

01:52:10.320 | and getting hot, which is a problem.

01:52:12.600 | That was the technical breakthrough that was realized

01:52:16.600 | by myself and at the time, my students and postdocs

01:52:20.160 | and colleagues at MIT, was that we saw the advent

01:52:24.360 | of this new superconducting material,

01:52:27.720 | which would allow us to access much higher magnetic fields.

01:52:30.640 | It's basically a next generation of the technology.

01:52:33.480 | And it was quite disruptive to fusion.

01:52:36.720 | That namely, what it would allow,

01:52:38.240 | that if we could get to this point

01:52:40.080 | where we can make the round 20 Tesla,

01:52:42.560 | we knew by the rules of tokamaks that this is going to be,

01:52:45.800 | is going to allow us to vastly shrink

01:52:49.040 | like the sizes of these devices.

01:52:50.520 | So it wouldn't take, although it's a worthy goal,

01:52:54.120 | it wouldn't take a seven nation international treaty

01:52:57.740 | basically to build it.

01:52:59.200 | You could build it with a company and a university.

01:53:01.880 | - So same kind of design,

01:53:03.160 | but now using the superconducting magnets.

01:53:05.400 | - Yeah, and if in fact, if you look at it,

01:53:07.200 | it's like, if you just expand the size of it,

01:53:10.680 | they're like, they look almost identical to each other

01:53:13.240 | because it's based on the,

01:53:14.400 | and actually that comes for a reason by the way,

01:53:16.000 | is that it also looks like a bigger version

01:53:18.440 | of the tokamak that we ran at MIT for 20 years,

01:53:22.160 | where we established the scientific benefits,

01:53:24.840 | in fact, of these higher magnetic fields.

01:53:27.280 | So that's the pathway that we're on.

01:53:29.000 | So I always say, so what does this mean?

01:53:31.000 | The context is different because it was made,

01:53:36.000 | because it's primarily being made

01:53:37.600 | by a private sector company spun out of MIT,

01:53:41.640 | because the way that it raised money

01:53:43.880 | and the purpose of the entity, which is there,

01:53:46.400 | is to make commercial fusion power plants,

01:53:48.740 | not just to make a scientific experiment.

01:53:51.240 | This is actually why we have,

01:53:52.680 | it's why we have a partnership, right?

01:53:55.440 | Is that our purpose at MIT

01:53:57.360 | is not to commercialize directly,

01:53:59.360 | but boy, do we want to advance the technology

01:54:01.560 | and the science that comes along this,

01:54:03.080 | and that's the reason we're sort of doing it together.

01:54:05.360 | - So it's MIT and Commonwealth Fusion Systems.

01:54:07.920 | So what's interesting to say about financing?

01:54:10.320 | And this seems like, from a scientific perspective,

01:54:13.920 | maybe not an interesting topic,

01:54:15.280 | but it's perhaps an extremely interesting topic.

01:54:17.840 | I mean, you can just look at the tension

01:54:19.200 | between SpaceX and NASA, for example.

01:54:22.320 | It's just clear that there's different financing mechanisms

01:54:24.920 | that can actually significantly accelerate

01:54:28.900 | the development of science and engineering.

01:54:32.080 | - It's great that you brought that up.

01:54:33.440 | We use several historic analogs,

01:54:36.160 | and one of them is around SpaceX,

01:54:37.560 | which is an appropriate one because space,

01:54:41.200 | putting things into orbit has a minimum size to it

01:54:45.160 | and integrated technological complexity

01:54:48.040 | and budget and things like this.

01:54:50.120 | So our point when we were talking about starting

01:54:54.000 | a fusion commercialization company,

01:54:56.820 | people look at you like,

01:54:58.240 | isn't this still really just a science experiment?

01:55:01.160 | But one of the things that we pointed to was SpaceX

01:55:04.280 | to say, well, tell me like 25 years ago,

01:55:06.880 | how many people would have voted that, you know,

01:55:09.320 | the leading entity on the planet to put things into orbit,

01:55:12.000 | it's a private company.

01:55:13.200 | People would have thought you were nutso, right?

01:55:15.400 | It's like, and what is interesting about SpaceX

01:55:19.240 | is that it proved it's more than actually just financing.

01:55:23.440 | It's really the purpose of the organization.

01:55:26.600 | So the purpose of a, and I'm not against public finance

01:55:30.400 | or anything like that, but the purpose of a public entity

01:55:33.640 | like NASA correctly, you know, speaks to the political,

01:55:38.640 | because the cost comes from the political, you know,

01:55:42.600 | assembly that is there, and I guess from us eventually

01:55:46.160 | as well too, but its purpose wasn't about like making

01:55:50.400 | a commercial product.

01:55:51.920 | It's about fundamental discovery and so forth,

01:55:54.560 | which is all really great.

01:55:56.360 | It's like, why did SpaceX, it's interesting,

01:55:59.840 | why did SpaceX succeed so well is because the idea was,

01:56:03.960 | it's like the focus that comes in the idea that you're going

01:56:08.280 | to relentlessly like reduce cost and increase efficiency

01:56:12.920 | is a drive that comes from the commercial aspect of it,

01:56:16.440 | right, and this also then changes the people in the teams,

01:56:21.260 | which are doing as well too, and in fact,

01:56:23.000 | trickles throughout the whole thing because the purpose

01:56:26.160 | isn't, while you're advancing things,

01:56:29.320 | like it's really good that we can put things in orbit

01:56:31.480 | a lot more cheaply, like it advances science,

01:56:34.020 | which is an interesting synergy, right?

01:56:35.760 | And it's the same thing that we think is gonna happen

01:56:38.500 | in fusion, that namely, this is a bootstrap effect

01:56:41.720 | that actually, that when you start to push yourself

01:56:44.860 | to think about near-term commercialization,

01:56:47.880 | it like allows the science to get in hand faster,

01:56:51.640 | which then allows the commercialization to go faster,

01:56:53.840 | and up we go.

01:56:55.500 | By the way, we've seen this also in another,

01:56:57.600 | again, you have to watch out with analogies

01:57:00.560 | 'cause they only can go so far, but like biotech

01:57:03.840 | is another one, like you look at the Human Genome Project,

01:57:06.640 | which was, it's sort of like, to me,

01:57:09.960 | that's like mapping the human genome is like,

01:57:12.880 | like that we can make net energy from fusion,

01:57:15.520 | like it's one of those like in your drawer that you go,

01:57:19.000 | this is a significant achievement by humanity,

01:57:21.680 | right, in this century, and there's the Human Genome Project

01:57:25.800 | fully government funded, it's gonna take 20, 25 years

01:57:29.920 | 'cause we basically know the technology,

01:57:32.480 | we're just gonna be really diligent, keep going,

01:57:34.560 | da, da, da, and then all of a sudden, what comes along?

01:57:37.600 | Disruptive technology, right?

01:57:40.300 | You can sequence, you know, shotgun sequencing

01:57:42.840 | and computer recognition patterns, and basically,

01:57:46.240 | oh, I can do this 100 times faster, like wow, right?

01:57:51.200 | So that's really the, you know, to me,

01:57:54.800 | the story about why we started,

01:57:56.920 | why we launched Commonwealth Fusion Systems

01:57:58.680 | was more than just about another source of funding,

01:58:03.080 | which it is a different source of funding

01:58:04.520 | 'cause it comes, it's also a different purpose,

01:58:06.880 | which is very important.

01:58:08.120 | - But there's also something about a mechanism

01:58:10.960 | that creates culture, so giving power to like a young

01:58:15.600 | student, ambitious student to have a tremendous impact

01:58:18.920 | on the progress of nuclear fusion creates a culture

01:58:22.260 | that actually makes progress more aggressively,

01:58:24.360 | like you said, when seven nations collaborate,

01:58:27.800 | it gives more incentive to the bureaucracy

01:58:29.840 | to slow things down, to kind of have,

01:58:31.680 | let's first have a discussion, and certainly don't give

01:58:34.680 | voice to the young, ambitious minds

01:58:36.840 | that are really pushing stuff forward.

01:58:38.920 | And there's something about like the private sector

01:58:41.640 | that rewards, encourages, inspires young minds

01:58:46.640 | to say in the most beautiful of ways, F you to the--

01:58:50.640 | (laughing)

01:58:52.040 | - It is, it is a lot. - To the boss.

01:58:53.680 | - Yeah, yeah. - To say like,

01:58:54.720 | we'll make it faster, we'll make it simpler,

01:58:56.400 | we'll make it better, we'll make it cheaper.

01:58:57.960 | - Yeah, and sometimes that brashness doesn't bear out,

01:59:00.960 | you know, that's an aspect that you just take

01:59:02.840 | a different risk profile as well too,

01:59:04.600 | but you're right, it's this, you know, of the,

01:59:07.880 | I mean, it was interesting, our own trajectory

01:59:10.280 | at the fusion center was like we were pushed

01:59:13.580 | into this place by necessity as well too

01:59:16.280 | because I told you we have, and we had operated

01:59:19.120 | for a long time a tokamak on the MIT campus,

01:59:23.520 | achieved these world records,

01:59:24.720 | like 100 million degree plasma and stuff,

01:59:26.760 | like wow, this is fantastic.

01:59:28.780 | But, you know, somewhat ironically I have to say

01:59:32.240 | is that it was like, oh, but we're not,

01:59:34.480 | this isn't the future of fusion anymore,

01:59:36.520 | like we're not, we're just gonna stop with small projects

01:59:39.120 | 'cause it's too small, right?

01:59:40.700 | So we need to really move on to these much bigger projects

01:59:43.880 | 'cause that's really the future of fusion.

01:59:45.880 | And so it was defunded and this basically put at risk,

01:59:49.760 | like we were going to essentially lose MIT

01:59:52.680 | in the ecosystem, really a fusion,

01:59:55.120 | both from the research but also clearly important

01:59:58.200 | from the educational part of it.

02:00:00.320 | So we, you know, we pushed back against this,

02:00:02.880 | we got a lifeline, we were able to go,

02:00:05.200 | and it was in this time scale that we basically

02:00:08.100 | came up with this idea, it's like, we should do this.

02:00:10.720 | And in the end it was all of those,

02:00:14.240 | the people who were in the C level of the company

02:00:17.040 | were all literally students who got caught in that,

02:00:19.840 | they were PhD students at the time.

02:00:21.880 | So you talk about enabling another generation,

02:00:24.880 | it's like, yeah, there you go, right?

02:00:27.400 | - So Spark gave-- - A lifeline.

02:00:30.320 | - A lifeline, gave fuel to the future center at MIT

02:00:33.440 | that it continues. - But it's way more than that.

02:00:35.360 | It wasn't just about like surviving

02:00:37.680 | for the sake of surviving, it was like,

02:00:39.880 | in the end for me it became like this,

02:00:42.200 | I remember the moment, you talk about these moments

02:00:44.380 | as a scientist and we were just like,

02:00:46.520 | we were working so hard about figuring out

02:00:48.520 | like, does this really, will this really work?

02:00:50.240 | Like, it's complex, like, does the magnet work?

02:00:53.560 | Does the interaction with the plasma work?

02:00:55.160 | Does all these things work?

02:00:56.280 | And it was just a grind, push, push, push, push.

02:00:59.080 | And I remember the moment 'cause I was sitting

02:01:02.080 | in my office in Brookline and there was just like,

02:01:05.680 | I read like, and I was in, I don't know, whatever,

02:01:07.760 | the 20th or 40th slide or something into it.

02:01:11.080 | And it was sort of that moment, like it just came together.

02:01:13.760 | And I like, I couldn't even sit down

02:01:16.440 | 'cause all it was just like, my wife was like,

02:01:18.040 | why are you walking around the apartment like this?

02:01:19.960 | Like, I just couldn't, I said, it's going to work.

02:01:22.560 | Like, it's going to work, like, holy cow.

02:01:24.800 | That moment of realization is like, kind of amazing.

02:01:28.280 | But it also brings the responsibility of making it work.

02:01:31.680 | - Yeah, how do you make it work?

02:01:32.520 | So, you mean like that magic realization

02:01:35.080 | that you can have this modern magnet technology

02:01:39.080 | and you can actually, like, why do we need to work

02:01:41.540 | with ITER, we can do it here?

02:01:43.000 | - Yeah, yeah, but it's interesting that ITER is,

02:01:47.120 | that one of the reasons that like,

02:01:49.920 | we started with a group of six of us at MIT.

02:01:52.440 | And then once we got some funding

02:01:54.240 | through the establishment of the company,

02:01:56.480 | it became a slightly larger.

02:01:58.160 | But in the end, we had a rather small team.

02:02:00.360 | Like, this was like a team of, you know,

02:02:02.760 | order of like 20 to 25 people designed Spark

02:02:05.680 | in like about two years, right?

02:02:08.800 | How does that happen?

02:02:09.880 | Well, we're clever, but you have to give ITER

02:02:12.720 | its due here as well too.

02:02:14.760 | Again, this is an aspect always of the bootstrap up.

02:02:18.080 | Like, I go back to the Human Genome Project.

02:02:21.000 | So, modern day genomics would not be possible

02:02:23.560 | without the underlying basis that came

02:02:25.760 | from setting that up.

02:02:27.360 | It had to be there.

02:02:28.240 | It had to be curiosity driven public program.

02:02:30.800 | It's the same with ITER, but because we had the tools

02:02:34.120 | that were there to understand ITER,

02:02:35.600 | we also had the tools to understand Spark.

02:02:37.740 | So, we parlayed those in an extremely powerful way

02:02:41.440 | to be able to tell us about what was going to happen.

02:02:43.720 | So, these things are never simple, right?

02:02:45.240 | It's like people look at this, go,

02:02:46.360 | "Oh, this means we should, like,

02:02:48.000 | "should we really have a public-based program about fusion

02:02:50.620 | "or should we have it all in the private?"

02:02:52.320 | It's like, no, the answer is neither way

02:02:54.440 | because in all these complex technologies,

02:02:56.680 | you have to keep pushing on all the fronts

02:02:58.360 | to actually get it there.

02:03:00.120 | - So, you know, the natural question when people hear

02:03:02.360 | breakthrough with the inertial confinement,

02:03:05.080 | with the magnetic confinement is,

02:03:06.980 | so, when will we have commercial reactors,

02:03:10.880 | power plants that are actually producing electricity?

02:03:13.720 | What's your sense looking out into the future?

02:03:17.840 | When do you think you can envision a future

02:03:19.960 | where we have actual electricity coming from nuclear fusion?

02:03:22.920 | - Partly driven by us, but in other places as well, too.

02:03:25.840 | So, there's the advent, what's so different now

02:03:29.440 | than three or four years ago.

02:03:31.080 | Like, we launched around four years ago.

02:03:33.780 | What's so different now is the advent of a very nascent,

02:03:38.040 | but seemingly robust, commercial fusion endeavor.

02:03:43.040 | So, it's not just Commonwealth Fusion Systems.

02:03:45.720 | There's something like 20-plus companies.

02:03:49.000 | - So, there's a sector now.

02:03:50.120 | - There's a sector.

02:03:51.560 | They actually have something called

02:03:52.840 | the Fusion Industry Association,

02:03:54.360 | which if your viewers wanna go see this,

02:03:56.560 | this describes the different,

02:03:58.080 | and they've got this plethora of approaches.

02:04:00.160 | Like, I haven't even described all the approaches.

02:04:02.080 | I've basically described the mainline approaches.

02:04:04.480 | And they're all at varying degrees of technical

02:04:07.920 | and scientific maturity with very huge,

02:04:10.920 | different balances between them.

02:04:13.280 | But what they share is that because they're going out

02:04:17.400 | and getting funding from the private sector,

02:04:20.120 | is that their stated goals are about getting fusion

02:04:25.040 | into place so that both it meets the investors' demands,

02:04:29.040 | which are interesting, right, and the timescales of that,

02:04:31.880 | but also it's like, well, there's gonna, and why?

02:04:34.560 | It's because it's easy.

02:04:36.280 | There's this enormous push, driver,

02:04:39.680 | about getting carbon-free energy sources

02:04:42.160 | out into the market.

02:04:43.240 | And whoever figures those out is going to be both very,

02:04:47.360 | it's gonna be very important geopolitically,

02:04:49.080 | but also economically as well too.

02:04:51.440 | So, it's a different kind of bet, I guess,

02:04:55.520 | or a different kind of gamble

02:04:56.760 | that you're taking with fusion,

02:04:58.080 | but it's so disruptive that it's like,

02:05:00.560 | there's essentially a class of investors and teams

02:05:04.080 | that are ready to go after it as well too.

02:05:06.400 | So, what do they share in this?

02:05:08.320 | They typically share getting after fusion on a timescale

02:05:12.520 | so that could it have any relevance

02:05:14.760 | towards climate change, battling climate change.

02:05:18.000 | And I would say this is difficult,

02:05:20.200 | but it's fairly easy 'cause it's math.

02:05:22.520 | So, what you do is you actually go to some target,

02:05:24.560 | like 2050 or 2060, something like this,

02:05:26.920 | and say, I wanna be blank percent of the world's market

02:05:30.600 | of electricity or something like that.

02:05:32.120 | And we know historically what it takes to evolve

02:05:36.320 | and distribute these kinds of technologies

02:05:38.120 | 'cause every technology takes some period of time,

02:05:40.920 | so-called S curve, it's basically,

02:05:42.600 | everything follows a logarithmic curve,

02:05:45.120 | exponential type curve,

02:05:46.280 | it's a straight line, a log plot.

02:05:48.160 | And like you look at wind, solar, fission,

02:05:51.320 | they all follow the same thing.

02:05:52.680 | So, it's easy, you take that curve and you go,

02:05:54.800 | that's slope and you work backwards.

02:05:56.520 | And you go, if you don't start in the early 2030s,

02:05:59.160 | like, it's not gonna have a significant impact

02:06:03.720 | by that time.

02:06:04.680 | So, all of them share this idea.

02:06:07.160 | And in fact, it's not just the companies now,

02:06:09.280 | the US federal government has a program

02:06:11.960 | that was started last year that said,

02:06:14.200 | we should be looking to try to get like the first,

02:06:17.000 | and what do I mean by, like, what does it mean to start?

02:06:19.120 | That you've got something that's putting electricity

02:06:21.080 | on the grid, a pilot, what we call it.

02:06:23.160 | And if that can get started, like in the early 2030s,

02:06:27.880 | the idea of ramping it up, you know, makes sense.

02:06:30.200 | That's math, right?

02:06:31.640 | So, that's the ambition, then the question is,

02:06:34.880 | and actually this is different

02:06:36.280 | because the government program,

02:06:38.360 | and they vary around in this.

02:06:39.800 | So, for example, the United Kingdom's government idea

02:06:42.680 | was to get the first one on by 2040.

02:06:45.520 | And China has ambitions probably middle 2030s,

02:06:50.000 | or maybe a little bit later.

02:06:52.240 | And Europe, you know, continental Europe,

02:06:55.320 | is a little bit, I'm not exactly sure where it is,

02:06:58.120 | but it's like later, it's like 2050 or 2060,

02:07:00.760 | 'cause it's mostly linked to the Eater timeline as well too.

02:07:03.760 | The fusion companies, which makes sense,

02:07:06.800 | it's like, of course they've got

02:07:07.760 | the most aggressive timelines.

02:07:09.000 | It's like, we're gonna map the human genome faster

02:07:10.840 | as well too, right?

02:07:12.080 | So, it's interesting about where we are.

02:07:14.480 | And I think, you know, we're not all the way there,

02:07:18.000 | but my intuition tells me we're probably gonna have

02:07:20.280 | a couple of cracks at it actually on that timeline.

02:07:23.960 | So, this is where we have to be careful though,

02:07:26.200 | you say commercial fusion.

02:07:28.080 | You know, what does that mean?

02:07:29.320 | Commercial fusion to me means that you're actually

02:07:32.200 | have a known quantity about what it costs,

02:07:36.120 | what it costs to build, and what it costs to operate,

02:07:38.760 | the reliability of putting energy on the grid.

02:07:41.480 | That's commercial fusion.

02:07:43.320 | So, it turns out that that's not necessarily

02:07:46.160 | exactly the first fusion devices

02:07:48.320 | that put electricity on the grid,

02:07:49.560 | 'cause you gotta, there's a learning curve

02:07:51.000 | to get like better and better at it.

02:07:53.600 | But that's probably, I would suspect,

02:07:56.720 | the biggest hurdle is to get to the first one.

02:07:59.240 | - The work I've done, the work I continue to do

02:08:01.720 | with autonomous vehicles and semi-autonomous vehicles,

02:08:03.840 | there's an interesting parallel there

02:08:05.080 | where a bunch of companies announced a deadline

02:08:08.200 | for themselves in 2020, '21, '22,

02:08:10.880 | and only a small subset of those companies

02:08:13.480 | have actually really pushed that forward.

02:08:15.920 | There's Google with Waymo, or Alphabet rather,

02:08:20.440 | and then there's Tesla with semi-autonomous driving

02:08:25.040 | in their autopilot, full self-driving mode.

02:08:27.440 | And those are different approaches.

02:08:30.800 | So, Tesla's achieving much, much higher scale,

02:08:33.800 | but the quality of the drive is semi-autonomous.

02:08:38.440 | I don't know if there's a metaphor or an analogy here.

02:08:41.080 | And then there's Waymo that's focusing

02:08:43.200 | on very specific cities, but achieving real,

02:08:46.360 | full autonomy with actual passengers,

02:08:48.700 | but the scale is much smaller.

02:08:50.260 | So, I wonder, just like you said,

02:08:52.220 | there would be these kinds of similar

02:08:53.640 | kind of really hard pushes.

02:08:56.400 | - Absolutely.

02:08:57.240 | So, actually, this is why I'm encouraged about Fusion.

02:09:00.800 | So, Fusion's still hard, let's let everyone be clear,

02:09:03.680 | because of the science underneath it

02:09:06.000 | of achieving the right conditions for the plasma

02:09:09.120 | basically is a yardstick that you have

02:09:11.920 | to put up against all of them.

02:09:13.640 | What's encouraging that I see in this,

02:09:16.040 | and it's actually what happens when you sort of

02:09:18.280 | let loose the creativity of this,

02:09:20.620 | is maybe I'll go back to first principles.

02:09:23.740 | So, Fusion is also a fairly strange,

02:09:27.100 | so if you think about building a coal plant,

02:09:29.260 | like burning wood and coal and gas

02:09:31.780 | is actually not that much different from each other,

02:09:34.020 | because they're kind of about the same physical conditions,

02:09:36.540 | and you get the fuel and you light it,

02:09:37.860 | and the Fusion is very, remember I told you

02:09:40.900 | that there's this condition of the temperature,

02:09:42.440 | which is kind of universal.

02:09:44.360 | But if you take the density of the fuel

02:09:47.020 | between magnetic Fusion and inertial Fusion,

02:09:49.640 | they're different by about a factor of 10 billion.

02:09:52.960 | So, this, and the density of the fuel really matters,

02:09:55.620 | and actually, so does the,

02:09:56.460 | and this means the energy confinement time

02:09:58.020 | is also different by a factor of 10 billion as well too,

02:10:00.740 | because it's the product of those two.

02:10:02.360 | So, one's really dense and short-lived,

02:10:04.960 | and the other one's really long-lived

02:10:06.420 | and actually under-dense as well too.

02:10:09.560 | So, what that means is that the way to get

02:10:15.420 | the underlying physical state is so different

02:10:17.900 | among these different approaches,

02:10:19.740 | what it lends itself to is, does this mean

02:10:23.020 | that eventual commercial products will actually

02:10:26.220 | fill different needs in the energy system?

02:10:29.020 | So, it sort of goes to your comment about,

02:10:31.220 | I have to suspect this, because anything

02:10:35.380 | that is high-tech and is like a really important

02:10:38.520 | thing in our economy, tends to never find its way

02:10:41.760 | as one, only one manifestation.

02:10:44.260 | Like, look at transportation as well too.

02:10:46.580 | We have scooters, Vespas, you know,

02:10:51.060 | overland trucks, cars, electric cars,

02:10:53.740 | of course we have these,

02:10:54.580 | because they meet different demands in it.

02:10:56.900 | So, what's interesting, you know,

02:10:58.420 | that I find fascinating now is that we have,

02:11:00.600 | in fusion, it's going to look like that,

02:11:03.020 | that probably there's, while the near-term

02:11:06.100 | focus is on electricity production,

02:11:08.340 | there might even be different kinds of markets

02:11:10.660 | that actually make sense in some places,

02:11:12.940 | less than others, it comes to trade-offs,

02:11:15.660 | 'cause we haven't really talked about the engineering yet,

02:11:17.540 | but the engineering really matters,

02:11:19.420 | like to the operation of the device.

02:11:22.340 | And so, it could be that, you know,

02:11:25.000 | I suspect what we'll end up with is several

02:11:27.500 | different configurations which have different features,

02:11:30.020 | which are trade-offs, basically, in the energy market.

02:11:33.420 | - What do you see as the major engineering

02:11:36.140 | or general hurdles that are in the way?

02:11:39.180 | - Yeah.

02:11:40.660 | So, the first one is just the cost

02:11:43.340 | of building a single unit.

02:11:46.300 | So, fusion has, and it's actually interesting,

02:11:48.700 | you talked about the different models that you have.

02:11:50.980 | So, fusion has, one of its interesting limitations

02:11:55.900 | is that it's very hard, almost at some point

02:11:59.420 | it becomes physically impossible to actually

02:12:01.340 | make small power units, like a kilowatt,

02:12:05.300 | a thousand watts, you know, which is like

02:12:07.180 | a personal home, like, you know,

02:12:08.740 | this is about a thousand watts,

02:12:10.220 | or your personal use of electricity

02:12:13.140 | is about like a thousand watts.

02:12:15.220 | This is basically impossible for a single unit to do this.

02:12:19.940 | So, like, you're not gonna have a fusion

02:12:22.540 | like power plant, like as your furnace

02:12:24.780 | or your electric heater in your home.

02:12:27.300 | And the reason for this comes from the fact

02:12:29.580 | that fusion relies on it being,

02:12:32.380 | it's not just that it's very hot,

02:12:34.100 | it's that the fusion power is the heating source

02:12:36.660 | to keep it hot.

02:12:37.500 | So, if you go too small, it basically

02:12:40.820 | just cannot keep it hot.

02:12:42.020 | So, it's interesting is that this,

02:12:45.060 | so this is one of the hard parts.

02:12:46.300 | So, this means that the individual units,

02:12:48.740 | you know, and it varies from concept to concept,

02:12:51.420 | but the National Academy's report that came out last year

02:12:55.580 | sort of put the benchmark as being like,

02:12:58.620 | probably the minimum size looks like

02:13:00.820 | around 50 million watts of electricity,

02:13:03.380 | which is like enough for like a small to,

02:13:06.180 | you know, mid-sized city actually.

02:13:08.700 | So, that is, so that's sort of like a scale challenge.

02:13:13.300 | And in fact, it's one of the reasons why

02:13:15.780 | in Commonwealth and in other private sector ones,

02:13:18.180 | like, they try to push this down actually

02:13:21.220 | of trying to get to these smaller units,

02:13:23.740 | just 'cause it reduces the cost of it.

02:13:25.860 | Then probably, obviously, I would say,

02:13:30.460 | it's an obvious one, like achieving the fusion state

02:13:32.980 | itself and high gain is a hard one.

02:13:36.100 | But we already talked about.

02:13:37.100 | What kind of hurdle, what kind of challenge is that?

02:13:39.220 | That's achieving the right temperature,

02:13:40.820 | density, and energy confinement time

02:13:42.780 | in the fuel itself, in the plasma itself.

02:13:45.420 | And so, some of the configurations

02:13:48.980 | which are being chosen are actually,

02:13:51.740 | have quite a ways to go, in fact, of seeing those.

02:13:54.140 | But what their consideration is, oh, yes,

02:13:57.500 | but by our particular configuration,

02:13:59.940 | the engineering simplicity confers

02:14:01.940 | like an economic advantage, even if we're behind

02:14:04.460 | in sort of an assigned sense, okay, which is fine.

02:14:07.820 | This is also what you get when you get an explosion

02:14:10.540 | in the private sector.

02:14:11.740 | You basically are distributing risks

02:14:13.500 | in different ways, right, which makes sense.

02:14:15.700 | All of that good, so what I would say

02:14:19.180 | is that the next hurdle to really overcome

02:14:22.500 | is about making that electricity.

02:14:24.980 | So, like, we need to see a unit or several units,

02:14:28.540 | like using fusion in some way to put

02:14:31.060 | a meaningful amount of energy on the grid.

02:14:33.620 | Because this starts giving us real answers

02:14:36.820 | as to like what this is going to look like.

02:14:40.540 | The full end-to-end process.

02:14:41.660 | The full end-to-end thing.

02:14:43.060 | So, Commonwealth's goal is that,

02:14:44.660 | I'll just comment to Commonwealth

02:14:46.780 | 'cause I'll take some, you know,

02:14:48.380 | I guess some credit for this, is that

02:14:50.780 | the origins of Commonwealth were, in fact,

02:14:53.900 | in examining that.

02:14:55.460 | Like, we could see this new technology coming forward,

02:14:58.020 | this new superconducting material,

02:15:00.180 | and the origins of our thought process

02:15:02.260 | were really around designing, effectively,

02:15:04.780 | the pilot plant or the commercial unit.

02:15:06.740 | It's called ARC, which is actually

02:15:08.820 | the step forward after SPARC.

02:15:10.780 | And that was the origins of it.

02:15:12.780 | So, all the things that were other parts

02:15:14.380 | of the plan, like SPARC and the magnet,

02:15:16.580 | were actually all informed totally

02:15:19.420 | by building something that was gonna

02:15:20.780 | put net electricity on the grid.

02:15:22.740 | And the timing of that, we still hope,

02:15:24.300 | is actually the early 2030s.

02:15:25.980 | - So, SPARC is the design of the Takamak

02:15:28.300 | and ARC is the actual full end-to-end thing.

02:15:30.340 | - Is like a thing that actually puts

02:15:31.660 | that energy on the grid.

02:15:32.700 | So, SPARC is named intentionally,

02:15:35.100 | that it's on for a short period of time,

02:15:38.300 | and it doesn't have a, it has, yeah,

02:15:41.140 | it's the spark of the fusion revolution

02:15:43.780 | or something like that, I guess we could call it.

02:15:46.940 | Yeah, so those are sort of the programmatic

02:15:50.820 | challenges of doing that.

02:15:52.060 | And you talked about SpaceX, so what has

02:15:57.060 | evolved even in the last year or so was,

02:16:00.020 | in fact, in March of 2022, the White House

02:16:03.580 | announced that it was going to start a program

02:16:06.260 | that kind of looks like a SpaceX analogy,

02:16:08.660 | that namely, wow, we've got these things

02:16:11.460 | in the private sector, we should leverage

02:16:13.380 | the private sector and the advantages

02:16:15.100 | of what they obtain, but also with the things,

02:16:17.740 | like this is gonna be hard, it's gonna take

02:16:20.540 | quite a bit of financing, so why don't we set up

02:16:23.060 | a program where we don't really get in the way

02:16:25.780 | of the private sector fusion companies,

02:16:27.340 | but we help them finance these difficult things,

02:16:29.580 | which is how SpaceX basically became successful

02:16:32.300 | through the COTS program, fantastic, right?

02:16:34.660 | And that's evolving as well, too,

02:16:36.140 | so the fusion ecosystem is almost unrecognizable

02:16:39.940 | from where it was like five years ago

02:16:41.860 | around those things.

02:16:42.900 | - How important is it for the heads of the companies

02:16:47.460 | that are working on nuclear fusion

02:16:48.860 | to have a Twitter account and to be quite,

02:16:51.620 | you said you don't use Twitter--

02:16:52.860 | - I don't use Twitter. - Very much.

02:16:54.780 | I mean, there is some element to,

02:16:57.140 | and I don't think this should be discounted,

02:16:58.860 | whatever you think about figures like Jeff Bezos

02:17:02.740 | with Blue Origin or Elon Musk with SpaceX.

02:17:05.620 | There is a science communication, to put it in nice terms,

02:17:10.620 | that's kind of required to really educate the public

02:17:15.300 | and get everybody excited and sell the sexiness of it.

02:17:18.460 | I mean, just even the videos of SpaceX,

02:17:20.460 | just being able to kind of get everybody excited

02:17:23.020 | about going out to space once again.

02:17:25.060 | I mean, there's all kinds of different ways of doing that,

02:17:26.860 | but I guess that's what companies do well,

02:17:29.980 | is to advertise themselves, to really sell themselves.

02:17:32.740 | - It is, yeah.

02:17:33.580 | Well, actually, I feel like one of the reasons

02:17:36.740 | on this podcast, and so I don't have an official role

02:17:40.940 | in the company, and one of the reasons for this

02:17:43.940 | was also that it's interesting 'cause when you come from,

02:17:48.180 | like you're running a company, it makes sense,

02:17:50.420 | they're promoting their own product and their own vision,

02:17:53.100 | which totally makes sense,

02:17:54.940 | but there's also a very important role for academics

02:17:58.660 | who have knowledge about what's going on,

02:18:00.900 | but are sufficiently distant from it

02:18:03.540 | that they're not fully only self-motivated

02:18:06.260 | just by their own projects or so forth.

02:18:09.180 | And for me, this is, I mean, we see particularly

02:18:13.420 | the problems of the distrust in technology,

02:18:16.200 | and then honestly in the scientific community as well too.

02:18:21.060 | It will be one of the greatest tragedies, I would say,

02:18:25.100 | that if we go through all of this and almost pull off

02:18:28.060 | what looks like a miracle, like technologic

02:18:30.700 | and scientific-wise, which is to make a fusion power plant,

02:18:33.860 | and then nobody wants to use it because they feel

02:18:37.300 | that they don't trust the people who are doing it

02:18:39.980 | or the technology.

02:18:41.500 | So we have to get so far out ahead of this.

02:18:44.680 | So I give lots of public lectures or things like this

02:18:48.220 | of accessing a larger range of people.

02:18:51.660 | We're not trying to hide anything.

02:18:53.340 | You can come and see, come do tours of our laboratory.

02:18:57.020 | In fact, I want to set those up virtually as well too.

02:18:59.100 | You might look at our Plasma Science and Fusion Center

02:19:02.140 | YouTube channel.

02:19:02.980 | So we are reaching out through those mediums,

02:19:04.980 | and it's really important that we do those things.

02:19:07.460 | But it's also, but also then realizing,

02:19:09.740 | setting up the realistic expectations of what we need to do.

02:19:12.940 | We're not there.

02:19:15.020 | We don't have commercial fusion devices yet.

02:19:17.340 | And you asked, like, what are the challenges?

02:19:19.860 | I'm not gonna get into any deep technical questions

02:19:23.020 | about what the challenges are, but it is,

02:19:25.700 | the pathway, not just to make fusion work technically,

02:19:31.380 | but to make it economically competitive and viable

02:19:34.380 | so that it's actually used out in the private sector

02:19:36.860 | is a non-trivial task.

02:19:38.900 | And it's because of the newness of it.

02:19:41.980 | Like, we're simultaneously trying to evolve the technology

02:19:46.180 | and make it economically viable at the same time.

02:19:49.180 | Those are two difficult coupled tasks.

02:19:52.940 | So my own research and my own drive right now

02:19:57.660 | is that fantastic Commonwealth Fusion Systems is set up.

02:20:00.540 | We have a commercialization unit of that particular kind,

02:20:03.860 | which is gonna drive forward a token back.

02:20:05.700 | In fact, I was just, there's discussions,

02:20:08.380 | or there's dialogues going on around the world

02:20:10.700 | with other kinds of ones, like stellarators,

02:20:12.660 | which prefer different kinds of challenges

02:20:15.060 | and economic advantages.

02:20:16.700 | But what we have to, I know what we have to have.

02:20:19.140 | What we have to have is a new generation

02:20:22.980 | of integrated scientists, technologists, and engineers

02:20:26.180 | that understand, like, how, what needs to get done

02:20:29.180 | to get all the way to the goal line.

02:20:31.220 | 'Cause we don't have them now.

02:20:32.460 | - So like a multidisciplinary team.

02:20:33.660 | - Yeah, exactly.

02:20:34.500 | - What's required, I mean, you've spoken about,

02:20:36.820 | you've said that fusion is, quote,

02:20:40.020 | "The most multidisciplinary field you can imagine."

02:20:44.060 | - Yes, yeah.

02:20:45.100 | - Why is that?

02:20:45.940 | What are the differences?

02:20:46.780 | - Well, 'cause most of our discussion that we've had so far

02:20:49.900 | is really like a physics discussion, really.

02:20:52.140 | So don't neglect physics as at the origin of this.

02:20:57.140 | But already we touched on plasma physics

02:20:59.860 | and nuclear physics, which are basically two,

02:21:03.420 | somewhat overlap, but independent disciplines.

02:21:06.100 | Then when it comes to the engineering,

02:21:08.300 | it's almost everything.

02:21:09.420 | So why is this?

02:21:10.900 | Well, let's build an electromagnet together, okay?

02:21:14.100 | What is this gonna take?

02:21:15.020 | It's gonna take, it's basically electrical engineering,

02:21:18.220 | computer, so you understand how it goes together,

02:21:21.540 | what happens, computational engineering

02:21:24.420 | to model this very complex integrated thing,

02:21:27.300 | materials engineering, because you're pushing materials

02:21:31.020 | to their limit with respect to stress and so forth.

02:21:34.100 | Takes cryogenic engineering, which is sort of

02:21:35.980 | a subdiscipline, but cooling things

02:21:37.620 | to extremely low temperatures.

02:21:39.460 | - Probably some kind of chemistry thing

02:21:40.660 | in there too.

02:21:41.500 | - Well, actually, yeah, which tends to show up

02:21:43.460 | in the materials.

02:21:44.300 | And that's just one of the subcomponents of it.

02:21:46.300 | Like almost everything gets hit in this, right?

02:21:49.260 | So you're, and you're also in a very integrated environment

02:21:52.580 | because in the end, all of these things,

02:21:54.860 | while you isolate them from each other in a physics sense,

02:21:57.940 | in an engineering sense, they all have to work

02:22:00.500 | like seamlessly together.

02:22:02.220 | So it's one of those, I mean, in my own career,

02:22:05.980 | I've basically done atomic physics, spectroscopy,

02:22:10.140 | plasma physics, ion etching.

02:22:13.940 | So this includes material science,

02:22:18.100 | something called MHD, magnetohydrodynamics.

02:22:23.500 | And now all the way through, like, I'm not even sure

02:22:26.660 | how many different careers I've had.

02:22:28.140 | It's also, by the way, this is also a recruiting stage

02:22:32.100 | for like young scientists thinking to come in.

02:22:34.140 | Like my comment to scientists, if you're bored in fusion,

02:22:36.700 | you're not paying attention, 'cause there's always

02:22:38.660 | something interesting to go and do.

02:22:41.660 | So that's a really important part of what we're doing,

02:22:45.500 | which isn't new in fusion, actually,

02:22:47.260 | and in fact is in the roots of what we've done at MIT.

02:22:50.900 | But holy cow, like the proximity of possibility

02:22:55.140 | of commercial fusion is the new thing.

02:22:57.820 | So my catchphrase is, like, you may be wondering,

02:23:00.580 | like, why weren't we doing all these things?

02:23:02.340 | Like, why weren't we pushing towards economic fusion

02:23:04.780 | and new materials and new methods of heat extraction

02:23:07.860 | and so forth?

02:23:08.700 | Because everybody knew fusion was 40 years away.

02:23:11.140 | And now it's four years away.

02:23:13.500 | - There is a history, like you said, 40, 30, whatever,

02:23:17.340 | that kind of old joke.

02:23:18.820 | There's a history of fusion projects that, you know,

02:23:23.820 | are characterized by cost overruns and delays.

02:23:26.540 | - Yeah.

02:23:27.700 | - How do you avoid this?

02:23:28.820 | How do you minimize the chance of this?

02:23:30.500 | - You have to build great teams, is one of them.

02:23:34.660 | It tends to be that the smaller,

02:23:37.260 | there's sort of an, I'm not an expert in this,

02:23:39.620 | but I've seen this enough integrated engineering teams.

02:23:41.580 | - Is there any equations?

02:23:42.780 | - Yeah, well, there's almost,

02:23:44.620 | I've seen this from enough teams.

02:23:45.940 | Like, I've seen also the futility of lone geniuses

02:23:48.740 | trying to solve everything by themselves.

02:23:50.420 | Like, no.

02:23:51.500 | But also organizations that have 10,000 people in them

02:23:54.340 | is just not, doesn't lend itself at all to innovation.

02:23:57.540 | So like one of our original sponsors

02:24:00.100 | and a good friend, Vinod Khosla,

02:24:01.380 | I don't know if you've ever talked to Vinod Khosla.

02:24:03.020 | He's a venture, he's got fantastic ideas

02:24:06.260 | about like the right sizes of teams

02:24:08.180 | and things that really innovate, right?

02:24:10.380 | And there is an optimum place in there

02:24:13.020 | is that you get enough cross discipline and ideas,

02:24:15.660 | but it doesn't become so overly bureaucratic

02:24:17.700 | that you can't execute on it.

02:24:19.420 | So one of the ways,

02:24:21.580 | and this was one of the challenges of Fusion

02:24:23.380 | is that everything was leading towards,

02:24:25.900 | like, I have to have like enormously large teams

02:24:30.300 | just to execute because of the scale of the project.

02:24:32.980 | The fact that now through both technology

02:24:37.020 | and I would argue financing innovation,

02:24:40.100 | we're driving to the point where it's smaller focused teams

02:24:43.460 | about doing those things.

02:24:44.420 | So that's one way to make it faster.

02:24:46.620 | The other way to make it faster is modularize the problem

02:24:49.740 | or parse the problem.

02:24:51.340 | So this is the other difficulty in Fusion

02:24:54.140 | is that you tend to look at this as like,

02:24:56.500 | oh, it's really just about making the plasma

02:24:59.020 | into this state, you know, here,

02:25:00.660 | that you get this energy gain.

02:25:02.260 | No, because in the end,

02:25:04.460 | if you can parse out the different problems of making that

02:25:08.060 | and then make it as separate as possible

02:25:09.620 | from extracting the energy

02:25:10.900 | and then converting it into electricity,

02:25:12.380 | the more separate those are,

02:25:13.980 | the better they are because you get parallel paths

02:25:16.140 | that basically mitigate risk.

02:25:17.900 | This is not new in Fusion, by the way,

02:25:19.260 | and this is the way that we attack

02:25:20.940 | most complex technological,

02:25:22.980 | you know, integrated technological challenges.

02:25:26.340 | - Have you by any chance seen some of the application

02:25:30.020 | of artificial intelligence, reinforcement learning,

02:25:32.180 | DeepMind has a nice paper, has a nice effort

02:25:35.860 | on basically using reinforcement learning

02:25:38.980 | for a learned control algorithm

02:25:40.380 | for controlling nuclear fusion.

02:25:42.260 | Do you find those kinds of,

02:25:44.940 | I guess you throw them under the umbrella

02:25:46.420 | of computational modeling.

02:25:47.940 | Do you find those interesting, promising directions?

02:25:50.780 | - They're all interesting.

02:25:51.980 | So when people, you know, I'll pull back,

02:25:55.180 | maybe a natural question is like,

02:25:57.340 | why is it different in Fusion?

02:25:58.860 | Like there's a long history to Fusion, right?

02:26:00.540 | It was going on for, like I told you,

02:26:02.260 | like stories from the late 1960s,

02:26:04.380 | like what's different now, right?

02:26:06.500 | So I think from the technology point of view,

02:26:10.020 | there's two massive things which are different.

02:26:11.940 | So one of them, you know, I'll be parochial,

02:26:14.100 | it's the advent of this new superconducting materials

02:26:16.460 | because the most mature ways that we understand

02:26:20.020 | about how we're gonna get to fusion power plants

02:26:21.740 | are magnetic fusion.

02:26:22.580 | And by the fact that you've got access

02:26:24.620 | to something which like changes the economic equation

02:26:28.100 | by an over an order of magnitude

02:26:29.940 | is just a totally, you know,

02:26:31.580 | and that wasn't that long ago,

02:26:33.180 | it was only September of 2021

02:26:34.900 | that we actually demonstrated the technology.

02:26:36.700 | That changes the prospects there.

02:26:39.460 | And the other one is computing

02:26:41.300 | and it's across the whole spectrum.

02:26:43.220 | It's not just in control of the Fusion device,

02:26:46.100 | it's actually in the, we actually use machine learning

02:26:48.740 | and things like this in the design of the magnet itself.

02:26:51.100 | It's an incredibly complex design space.

02:26:53.340 | So you use those tools.

02:26:55.620 | The simulation of the plasma itself is actually,

02:26:59.100 | we're at a totally different place than we were

02:27:02.060 | because of those things.

02:27:02.900 | So those are the two big drivers that I see actually

02:27:06.260 | that make it different.

02:27:08.380 | And actually, and it's interesting,

02:27:09.860 | both those things self-enforce

02:27:12.700 | about what you asked about before,

02:27:13.940 | like how do you avoid delays and things?

02:27:15.700 | Well, it's by having smaller teams

02:27:18.260 | that can actually execute on those.

02:27:20.140 | But now you can do this because the new magnets

02:27:23.980 | make the devices all smaller

02:27:26.100 | and the computing means your human effectiveness

02:27:29.140 | about exploring the optimization space is way better.

02:27:32.340 | It's like, they're all interlinked to each other.

02:27:34.180 | Plus the modularization, like you said,

02:27:35.900 | and it's everything just kind of works together

02:27:37.620 | to make smaller teams more effective, move faster.

02:27:40.060 | And it's actually, and it's through that learned experience.

02:27:42.740 | I mean, of the things that I'm the most proud of

02:27:45.740 | about what came out, in fact, the origins of thinking

02:27:48.620 | about how we would use

02:27:49.700 | the high temperature superconducting magnets

02:27:53.180 | came out of my design class at MIT.

02:27:56.580 | And in the design class, like one of the features

02:27:58.820 | that I kept, I mean, it was interesting,

02:28:00.380 | I actually learned, I really learned along

02:28:02.380 | with the students about this,

02:28:03.620 | but like this insistence on the features,

02:28:05.620 | like we can't have so many coupled, integrated,

02:28:09.300 | hard technology developments.

02:28:10.900 | Like we have to separate these somehow.

02:28:12.900 | So we worked and worked and worked at this.

02:28:14.620 | And in fact, that's what really, in my opinion,

02:28:17.860 | the greatest advantage of the arc design

02:28:19.980 | and built into the Commonwealth Fusion System idea

02:28:24.420 | is like to parse out the problems.

02:28:26.260 | Like how can we attack these in parallel?

02:28:28.620 | Yeah, and so it really comes to,

02:28:32.020 | we talked about philosophy, it's like a design philosophy.

02:28:34.820 | Like how do you attack these kinds of problems?

02:28:37.620 | And you do it like that.

02:28:39.540 | - And also, like you mentioned offline,

02:28:41.020 | that there's a power to, as part of a class,

02:28:46.020 | to design a nuclear fusion.

02:28:49.580 | - Well, it's...

02:28:50.420 | - Power plan.

02:28:51.260 | (laughing)

02:28:52.080 | - Well, it is...

02:28:52.920 | - And then make it a reality.

02:28:53.740 | - And it's hard to imagine a more powerful force

02:28:56.300 | than like 15 MIT PhD students,

02:28:59.020 | like working together towards solving a problem.

02:29:01.980 | And what I always, in fact, we just,

02:29:04.820 | we recently just taught the most recent,

02:29:07.780 | I say I teach it, I mean, I guide it actually,

02:29:10.900 | the most recent version of this,

02:29:12.220 | where they actually designed,

02:29:13.860 | based on this National Academies report,

02:29:15.820 | they actually designed like a pilot plant

02:29:18.860 | that has basis and similarities to what we had done before.

02:29:21.700 | But I kept wanting to like push the envelope

02:29:24.340 | and where they are.

02:29:25.180 | It's like the creativity and the energy

02:29:30.060 | that they bring to these things is kind of like,

02:29:32.580 | it keeps me going, like I'm not gonna retire anytime soon,

02:29:35.980 | when I keep seeing that kind of dedication,

02:29:37.860 | and it's wonderful around in that.

02:29:40.580 | It almost, not to overuse a,

02:29:42.740 | or to paraphrase something, right,

02:29:46.260 | which is that the famous quote by Margaret Mead,

02:29:51.260 | never doubt that a small group of dedicated persons

02:29:55.820 | will change the world.

02:29:56.900 | Indeed, it's the only thing that ever has.

02:29:59.780 | - I mean, that's just such a powerful

02:30:01.500 | and inspiring thing for an individual.

02:30:04.260 | Find the right team, be part of that,

02:30:05.900 | and then you, yourself, your passion,

02:30:07.940 | your efforts could actually make a big change,

02:30:10.420 | a big impact.

02:30:11.260 | I gotta ask you, so it's,

02:30:15.220 | it's a whole 'nother different conversation,

02:30:17.420 | I'm sure, to have, but nuclear power as it currently stands,

02:30:21.460 | so using fission is extremely safe,

02:30:26.020 | despite public perception.

02:30:27.260 | - It is the safest, actually.

02:30:28.860 | - So that's a whole 'nother conversation,

02:30:30.540 | but almost like a human, bureaucratic,

02:30:34.220 | physics, engineering question of what lessons do you draw

02:30:39.220 | from the catastrophic events

02:30:44.140 | where the power plants did fail,

02:30:47.060 | so Chernobyl and Three Mile Island,

02:30:48.780 | Chernobyl, what lessons do you draw?

02:30:50.380 | - Actually, Three Mile Island wasn't really a disaster,

02:30:52.220 | 'cause nothing escaped from the thing,

02:30:53.420 | but Chernobyl and Fukushima had obvious consequences

02:30:58.420 | in the populations that live nearby.

02:31:01.220 | - What lesson do you draw from those

02:31:03.780 | that you can carry forward to fusion?

02:31:05.860 | Now, I know there's, you can say that you're not gonna have

02:31:08.380 | the same kind of issues, but it's possible that

02:31:11.260 | the same folks also said they're not gonna be,

02:31:13.580 | have those same kind of issues.

02:31:15.180 | We humans, the human factor,

02:31:17.260 | we haven't talked about that one quite as much,

02:31:19.420 | but it's still there.

02:31:20.380 | - So to be clear, so fusion has intrinsic safety

02:31:24.520 | with respect to it can't run away,

02:31:27.300 | those are physics bases.

02:31:29.460 | Technology and engineering bases of running a,

02:31:32.100 | again, anything that makes large amounts of power

02:31:34.700 | and heats things up has got intrinsic safety in it,

02:31:37.580 | and by the fact that we actually produce

02:31:40.060 | very energetic particles, this doesn't mean

02:31:42.460 | that there's no radiation involved in,

02:31:44.860 | ionizing radiation to be more accurate.

02:31:47.940 | In fusion, it's just that it's in a very different

02:31:51.020 | order of magnitude, basically.

02:31:53.300 | So what are the lessons in fusion?

02:31:56.820 | So one of them is make sure that you're looking at aspects

02:32:01.820 | of the holistic environmental and societal footprint

02:32:07.500 | that the technology will have.

02:32:09.460 | As technologists, we tend not to focus on these,

02:32:13.460 | particularly in early stages of development.

02:32:15.780 | Like we just want something that works, right?

02:32:18.700 | But if we come with just something that works,

02:32:21.020 | but doesn't actually satisfy the societal demands

02:32:24.440 | for safety and for, I mean, we will have materials

02:32:28.040 | that we have to dispose of out of fusion,

02:32:29.900 | just this is, but there's technological questions

02:32:33.220 | about what that looks like.

02:32:34.800 | So will this look like something that you have to

02:32:37.620 | put in the ground for 100 years or five years?

02:32:41.220 | And the consequences of those are both economic

02:32:44.100 | and societal acceptance and so forth,

02:32:46.300 | but don't bury those.

02:32:47.500 | Like bring these up front, talk to people about them,

02:32:51.100 | and make people realize that you're actually,

02:32:53.740 | the way I would look at it is that you're making fusion

02:32:55.740 | more economically attractive by making it

02:32:57.860 | more societally acceptable as well too.

02:33:00.500 | And then realize is that, I think there's a few

02:33:04.460 | interesting boundaries, basically.

02:33:06.900 | So one of them, speaking of boundaries,

02:33:09.180 | that successful fusion devices, I'm pretty sure

02:33:12.860 | will require that you don't have to have an evacuation

02:33:16.500 | plan for anybody who lives at the site boundary.

02:33:19.140 | So this has implications for what we build

02:33:23.980 | from a fusion engineering point of view,

02:33:26.140 | but has major implications for where you can site

02:33:29.020 | fusion devices, right?

02:33:30.880 | So in many ways, it becomes more like, well,

02:33:32.900 | we have fences around industrial heat sources

02:33:35.860 | and things like this for a reason, right?

02:33:37.060 | For personal safety.

02:33:38.420 | It looks more like that, right?

02:33:40.180 | It's not quite as simple as that,

02:33:41.420 | but that's what it should look like.

02:33:43.140 | And in fact, we have research projects going on right now

02:33:45.660 | at MIT that are trying to push the technologies

02:33:48.700 | to make it more look like that.

02:33:50.780 | I think that those are key.

02:33:52.140 | And then in the end, as I said,

02:33:55.020 | so Chernobyl is physically impossible,

02:33:57.180 | actually, in a fusion system.

02:33:59.660 | - From a physics perspective.

02:34:00.580 | - From a physics perspective.

02:34:01.780 | You can't run away like it did at Chernobyl,

02:34:03.860 | which was basically human error of letting

02:34:07.140 | the reactors run out of control, essentially.

02:34:10.060 | - Human error can still happen with fusion-based reactors.

02:34:13.060 | - Yeah, but in that one, if human error occurs,

02:34:15.500 | then it just stops and this is done.

02:34:18.300 | And all of those things, this is the requirement

02:34:20.420 | of us as technologists and developers of this technology

02:34:24.860 | to not ignore that dimension, in fact, of the design.

02:34:28.340 | And that's why me personally, I'm actually

02:34:31.740 | pouring myself more and more into that area

02:34:34.220 | because this is going to be, I actually really think

02:34:36.940 | it is an aspect of the economic viability of fusion

02:34:39.740 | because it clearly differentiates ourselves

02:34:42.660 | and also sets us up to be about what we want fusion to be,

02:34:45.420 | is that, again, on paper, fusion can supply

02:34:48.220 | all of our energy, like all of it.

02:34:51.020 | So this means I want it to be like

02:34:53.140 | really environmentally benign,

02:34:55.340 | but this takes engineering ingenuity, basically, to do that.

02:34:58.980 | - Let me ask you some wild out there questions.

02:35:01.380 | - Sure.

02:35:02.300 | - So for--

02:35:03.140 | - We've been talking too much, you know.

02:35:04.460 | (laughing)

02:35:06.700 | - Simple, practical things in everyday life.

02:35:11.060 | No, only revolutionizing the entire energy infrastructure

02:35:14.340 | of human civilization, yes.

02:35:15.660 | But, so cold fusion, this idea, this dream,

02:35:20.660 | this interesting physical goals seem to be impossible,

02:35:26.700 | but perhaps it's possible.

02:35:28.300 | Do you think it is possible?

02:35:29.420 | Do you think down the line, somewhere in the far distance

02:35:34.220 | it's possible to achieve fusion at low temperature?

02:35:37.960 | - It's very, very, very unlikely.

02:35:41.900 | And this comes from, so this would require

02:35:46.620 | a pretty fundamental shift in our understanding of physics,

02:35:51.620 | as we know it now.

02:35:53.140 | And we know a heck of a lot about

02:35:55.180 | how nuclear reactions occur.

02:35:58.700 | By the way, what's interesting is that there's,

02:36:00.660 | they actually have a different name for it.

02:36:02.140 | They call it LEANER, like low energy nuclear reactions.

02:36:05.500 | But we do have low energy nuclear reactions.

02:36:07.340 | We know these, it's because these come from,

02:36:09.980 | particularly the weak interaction,

02:36:12.580 | the weak force, nuclear force.

02:36:15.300 | And so it's, at this point, you know, as a scientist,

02:36:20.300 | you always keep yourself open, because,

02:36:22.460 | but you also demand proof, right?

02:36:24.140 | And that's the thing.

02:36:24.980 | - It almost requires a breakdown

02:36:26.460 | on the theoretical physics side.

02:36:28.140 | So something, some deeper understanding

02:36:29.860 | about quantum mechanics, so the quantum tunneling,

02:36:32.460 | some weird.

02:36:33.620 | - Yeah, and people have looked at that,

02:36:35.820 | but even like something like quantum tunneling

02:36:38.100 | has a limit as to what it can actually do.

02:36:40.060 | So there are people who are genuine, you know,

02:36:43.380 | that really want to see it make,

02:36:45.220 | but, you know, it sort of goes to the extort,

02:36:47.460 | I mean, we know fusion happens at these high energies,

02:36:51.780 | like, we know this extremely accurately.

02:36:54.900 | And I can show you a plot that shows that

02:36:57.380 | as you go to lower and lower energy,

02:36:58.780 | it basically becomes immeasurable.

02:37:00.740 | So if you're going down this other pathway,

02:37:03.300 | it means there's really a very different

02:37:07.100 | physical mechanism involved.

02:37:09.540 | So all I would say is that I actually poke in my head

02:37:14.540 | once in a while to see what's going on in that area.

02:37:17.940 | And as scientists, we should always try

02:37:20.420 | to make ourselves open.

02:37:21.820 | And, but in this one, it's like,

02:37:25.140 | but show me something that I can measure

02:37:28.700 | and that is repeatable, and then it's gonna take

02:37:31.740 | more extraordinary effort.

02:37:33.140 | And to date, this has not met that threshold,

02:37:35.940 | in my opinion.

02:37:36.780 | - So even more so than just mentioning,

02:37:40.660 | or in that question, thinking about people

02:37:43.060 | that are claiming to have achieved cold fusion,

02:37:45.460 | I'm more thinking even about people

02:37:48.220 | who are studying black holes,

02:37:49.900 | and they're basically trying to understand

02:37:53.220 | the function of theoretical physicists.

02:37:56.420 | They're doing the long haul, trying to investigate,

02:38:00.340 | like, okay, what is happening at the singularity?

02:38:02.660 | What is this kind of holographic projections on a plate,

02:38:07.660 | these weird freaking things that are out there

02:38:10.660 | in the universe, and somehow, accidentally,

02:38:12.940 | they start to figure out something weird.

02:38:15.460 | - Weird, yeah.

02:38:16.300 | - And then all of a sudden--

02:38:17.620 | - There's weirdness all over the place already, yeah.

02:38:20.140 | - Somehow that weirdness will, I think,

02:38:22.420 | on a time scale probably of 100 years or so,

02:38:24.860 | that weirdness will open.

02:38:26.340 | It just seems like nuclear fusion and black holes

02:38:31.740 | and all of this are next-door neighbors

02:38:34.340 | a little bit too much for, like, you'll find something.

02:38:37.460 | Interesting.

02:38:38.300 | - Well, let me tell you a story about this.

02:38:40.340 | It's a real story.

02:38:41.260 | So there were really, really clever scientists

02:38:46.940 | in the end of the late 1800s in the world.

02:38:50.620 | You talk about, like, James Clerk Maxwell,

02:38:52.980 | and you talk about Lord Kelvin,

02:38:54.900 | and you talk about Lorentz, actually,

02:38:56.420 | who named after these other ones,

02:38:58.180 | and on and on and on, and like Faraday,

02:39:01.420 | and they discovered electromagnetism, holy cow,

02:39:04.220 | and it's like, they figure out all these things,

02:39:07.140 | and yet there were these weird things going on

02:39:12.140 | that you couldn't quite figure out.

02:39:14.260 | It's like, what the heck is going on with this, right?

02:39:17.580 | By the way, we teach this all the time

02:39:19.180 | in physics classes, right?

02:39:21.300 | So what was going on?

02:39:22.540 | Well, there's just a few kind of things unchecked,

02:39:27.540 | but basically, we're at the end of discovery

02:39:29.700 | 'cause we figured out how everything works,

02:39:31.820 | 'cause we've got basically Newtonian mechanics,

02:39:34.660 | and we've got Maxwell's equations,

02:39:36.420 | which describe basically how matter gets pushed around

02:39:39.500 | and how electromagnetism works.

02:39:41.060 | Holy cow, what a feat.

02:39:42.940 | But there were these few nagging things.

02:39:45.580 | Like, for instance, there's certain kinds of rocks

02:39:48.740 | that for some reason, like if you put a photographic plate

02:39:51.300 | around it, it gets burned, or it gets an image on it.

02:39:55.100 | Like, well, where's the electromagnetism in that?

02:39:58.260 | There's no electromagnetic properties of this rock.

02:40:00.860 | Oh yeah, and the other thing too is that

02:40:03.420 | if I take this wonderful classical derivation

02:40:06.820 | of something that is hot, about how it releases radiation,

02:40:11.460 | everything looks fantastic, perfect match.

02:40:15.380 | Oh, until I get to high frequencies of the light,

02:40:20.060 | and then it basically just, the whole thing falls apart.

02:40:22.420 | In fact, it gives a physical explanation,

02:40:24.740 | which is total nonsense.

02:40:26.460 | It tells you that every object should basically

02:40:28.980 | be producing an infinite amount of heat.

02:40:31.860 | And by the way, here's the sun, and we can look at the sun,

02:40:35.940 | and we can figure out it's made out of hydrogen.

02:40:37.900 | And Lord Kelvin actually made a very famous calculation

02:40:41.380 | who was basically one of the founders of thermodynamics.

02:40:44.300 | So you look at the hydrogen, hydrogen has a certain

02:40:47.100 | energy content, you know, the latent heat, basically,

02:40:49.460 | of hydrogen, we know the mass of the sun

02:40:51.580 | because we knew the size of it, and he conclusively proved

02:40:54.740 | that basically, the sun could only make net energy

02:40:58.860 | for about two or 3,000 years.

02:41:01.180 | So therefore, all this nonsense about deep,

02:41:03.900 | because clearly the sun can only last

02:41:05.860 | for two or 3,000 years, if you think about the,

02:41:08.460 | and this is basically the chemical energy content

02:41:10.420 | of hydrogen, and what comes along?

02:41:12.620 | And one decade, basically, one guy sitting

02:41:16.180 | in a postal office in Switzerland figures out

02:41:19.620 | that all of these, you know, Einstein, of course,

02:41:22.180 | which was, like, figured out all of this,

02:41:24.740 | like, took these seemingly unconnected things,

02:41:28.100 | and it's like, boom, there it is.

02:41:29.660 | This is what, it wasn't just him, but it was,

02:41:31.300 | like, there's quantum physics, like,

02:41:32.860 | this explains this other disaster.

02:41:34.940 | And then this other guy, my hero, Ernest Rutherford,

02:41:37.740 | experimentalist, did the most extraordinary experiment,

02:41:42.060 | which was that, okay, they had these funny rocks.

02:41:45.740 | They emitted these particles.

02:41:46.900 | In fact, they called them alpha particles,

02:41:48.900 | alpha, just A in the alphabet, right?

02:41:50.460 | 'Cause it was the first thing that they discovered.

02:41:52.860 | And what were they doing?

02:41:53.820 | So they were taking these alpha particles,

02:41:56.940 | and by the way, I do this to all my students,

02:41:58.820 | 'cause it's a demonstration of what you should be

02:42:00.660 | as a good scientist.

02:42:02.220 | So he took these alpha things,

02:42:03.540 | and he was a classically trained physicist,

02:42:05.660 | knew everything about momentum scattering

02:42:07.780 | and so forth and like that, and he took this,

02:42:10.180 | and these alpha, which clearly were some kind of energy,

02:42:13.300 | but they couldn't quite figure out what it was.

02:42:14.860 | So he said, "Let's try to figure that,

02:42:16.020 | we'll actually use this to try to probe the nature of matter."

02:42:18.700 | So he took this, took these alpha particles,

02:42:22.060 | and a very, very thin gold foil.

02:42:24.420 | And so what you wanted to see was that

02:42:25.860 | as they were going through,

02:42:27.540 | the way that they would scatter based on classical,

02:42:29.740 | in fact, the Coulomb collision,

02:42:31.260 | based on classical mechanics,

02:42:32.900 | this will tell me, reveal something

02:42:35.700 | about what the nature of the charge distribution is

02:42:38.300 | in matter, because they didn't know,

02:42:40.140 | like where the hell is this stuff coming from?

02:42:42.020 | Even though they'd solved electromagnetism,

02:42:44.060 | they didn't know like what made up charges.

02:42:46.820 | Okay, very interesting.

02:42:48.540 | Through it goes, and so what did you set up?

02:42:51.780 | So it turns out in these experiments,

02:42:53.700 | what you did was, because if these so-called alphas,

02:42:57.940 | which actually now we know is something else,

02:43:00.700 | as they go through, they would deflect,

02:43:02.660 | how much they deflect tells you

02:43:03.980 | how strong an electric field they saw.

02:43:06.140 | So you put detectors, 'cause if you put

02:43:08.260 | like a piece of glass in front of this,

02:43:10.460 | what will happen is that when the alpha particle hits,

02:43:12.380 | it literally gives a little, boop,

02:43:14.020 | a little point of light like this.

02:43:15.620 | It scintillates, a little blue flash.

02:43:18.140 | So he would train his students or postdocs

02:43:20.180 | or whatever the heck they were at the time,

02:43:21.740 | you have to train yourself,

02:43:22.780 | 'cause you have to put yourself in the dark

02:43:24.300 | for like hours to get your eyes adjusted.

02:43:27.020 | And then they would start the experiment

02:43:28.420 | and they would sit there and literally count the things.

02:43:30.820 | And they could see this pattern developing,

02:43:32.580 | which was revealing about what was going on.

02:43:35.460 | But there was also another part of the experiment,

02:43:37.300 | which was that, it's like, here's the alphas,

02:43:41.180 | here's the source, they're going this way.

02:43:43.260 | They could tell they were going in one direction only,

02:43:44.980 | basically, they're going in this direction.

02:43:47.340 | And you put all these over here,

02:43:48.500 | 'cause you wanna see how they deflect and bend through it.

02:43:50.740 | But you put a control in the experiment,

02:43:53.060 | which you basically put glass plates back here,

02:43:58.060 | because obviously everything should just deflect,

02:44:00.940 | but nothing should bounce back.

02:44:02.580 | So it's a control in the experiment.

02:44:05.380 | But what did they see?

02:44:06.780 | They saw things bouncing back.

02:44:10.100 | Like, what the hell?

02:44:12.860 | Like, that fit no model of any idea, right?

02:44:16.860 | But Rutherford refused to ignore what was a clear,

02:44:21.580 | like, they validated it, and he sat down

02:44:24.180 | and based on classical physics,

02:44:25.780 | he made the most extraordinary discovery,

02:44:28.620 | which was the nucleus,

02:44:30.540 | which is a very, very strange discovery.

02:44:33.460 | What do I mean by that?

02:44:34.580 | 'Cause what he could figure out from this

02:44:35.900 | is that in order for these particles to bounce back

02:44:39.620 | and hit this plate, they were hitting something

02:44:42.180 | that must be heavier than them,

02:44:45.140 | and that basically something like 99.999% of the mass,

02:44:50.140 | of the matter that was in this gold foil

02:44:52.700 | was in something that contained

02:44:54.540 | about one trillionth of the volume of it.

02:44:57.420 | And that's called the nucleus.

02:45:00.740 | And until, and you talk about, so how revealing is this?

02:45:03.860 | It's like, this totally changes your idea of the universe

02:45:07.740 | because a nucleus is a very unintuitive,

02:45:10.380 | non-intuitive thing.

02:45:11.780 | It's like, why is all the mass in something

02:45:14.420 | that is like zero, like, basically it was the realization

02:45:17.540 | that matter is empty.

02:45:19.340 | It's all empty space.

02:45:21.100 | - Yeah, and that changes everything.

02:45:22.180 | - And it changes everything.

02:45:24.100 | Until you had that, like, you had steam engines,

02:45:26.300 | by the way, you had telegraph wires,

02:45:27.740 | you had all those things.

02:45:28.980 | But that realization, like, opened up,

02:45:31.620 | those two realizations opened up everything,

02:45:34.260 | like lasers, all these things about the modern world

02:45:37.260 | of what we use, and that set it up.

02:45:40.140 | So all I would point out is that there's a story already

02:45:42.700 | that sometimes there's these nagging things

02:45:45.220 | at the edge of science that, you know,

02:45:47.180 | we seem, we pat ourselves on the back

02:45:49.460 | and we think we got everything under control.

02:45:51.420 | Of course, by the way, that was the origin of also,

02:45:54.500 | that it, think about this, that was 1908.

02:45:57.300 | It took like another 20-some years

02:46:00.860 | before people put that together with,

02:46:02.900 | that's the process that's powering stars.

02:46:05.520 | It was the rearrangement of those nuclei, not atoms.

02:46:09.180 | That's why Calvin wasn't wrong,

02:46:11.700 | he just was working with the wrong assumptions, right?

02:46:14.340 | So fast forward to today, like, what would this mean?

02:46:17.540 | Well, there's a couple of things like this

02:46:19.060 | that sit out there in physics,

02:46:20.580 | and I'll point out one of them, which is very interesting.

02:46:22.980 | We don't know what the hell makes up 90%

02:46:25.140 | of the mass in the universe.

02:46:27.220 | So, you know, the search for dark matter, right?

02:46:29.580 | What is it?

02:46:30.420 | We still haven't discovered it.

02:46:32.020 | 90% of the mass of the universe is undetectable.

02:46:36.280 | Like, what?

02:46:38.260 | - And then, you know, and dark energy,

02:46:39.700 | and again, black holes are the window into this.

02:46:42.700 | - Well, and black holes, I mean,

02:46:44.420 | sometimes black holes are way better understood

02:46:47.340 | than those things as well, too.

02:46:49.140 | So, all it tells us is that we shouldn't have hubris

02:46:51.540 | about the ideas that we understand everything.

02:46:54.420 | And when we, you know, who knows what the next

02:46:56.980 | major intellectual insight will be

02:47:00.100 | about how the universe functions.

02:47:02.260 | - And actually, I think Rutherford is the one

02:47:05.340 | who's attributed at least that quote,

02:47:08.020 | that physics is the only real science.

02:47:10.380 | Everything else is stamp collecting, right?

02:47:12.500 | So, there's--

02:47:13.740 | - I'm sorry, he's my hero,

02:47:14.620 | but I'll slightly disagree with that, yes.

02:47:18.180 | - Well, no offense to stamp collecting.

02:47:19.940 | It's very important, too.

02:47:21.020 | (laughing)

02:47:22.020 | But, you know, you have to have humility

02:47:23.820 | about the kind of disciplines that make progress

02:47:26.340 | at every stage in science.

02:47:29.140 | - Yeah, exactly.

02:47:29.980 | Physics did make a huge amount of progress

02:47:32.180 | in the 20th century, but it's possible

02:47:33.980 | that other disciplines start to step in.

02:47:35.820 | - Yeah, but Rutherford couldn't imagine

02:47:37.460 | like mapping the human genome

02:47:39.060 | because he didn't even know about DNA.

02:47:40.860 | - Yeah, or computers, really.

02:47:42.340 | - Or computers.

02:47:43.180 | - He really probably didn't think deeply about computation.

02:47:45.060 | - And who knows, it's like, is it,

02:47:46.340 | here's a wild one, what if like the next great revelation

02:47:50.980 | to humanity about the universe is not done

02:47:53.580 | by the human mind?

02:47:54.620 | - That seems increasingly more likely.

02:47:57.460 | - Likely, yeah, yeah, yeah.

02:47:58.460 | And then you start to ask deep questions

02:48:00.020 | about what is the purpose of science?

02:48:02.060 | For example, if AI system will design

02:48:07.060 | a nuclear fusion reactor better than humans do,

02:48:10.860 | but we don't quite understand how it works,

02:48:12.820 | and the AI can't, we know that it works.

02:48:15.780 | We can test it very thoroughly,

02:48:17.460 | but we don't know exactly what the control mechanism is,

02:48:21.140 | maybe what the chemistry, the physics is.

02:48:23.700 | AI can't quite explain it, they just can't.

02:48:25.780 | It's impenetrable to our consciousness, basically,

02:48:28.940 | trying to hold it all together.

02:48:30.220 | - And then, okay, so now we're living in that world

02:48:32.700 | where many of the biggest discoveries

02:48:34.860 | are made by AI systems.

02:48:36.260 | - Yeah.

02:48:37.100 | - As if we weren't going big.

02:48:40.380 | - Yeah, I say, again, I'll point out,

02:48:43.300 | like when my godmother was born,

02:48:45.820 | like none of this was in front of us, right?

02:48:47.980 | It's like, we live in an amazing time.

02:48:49.940 | It's like, right, like my grandfather, you know,

02:48:53.060 | plowed fields with a horse.

02:48:56.100 | I get to work on designing fusion reactors.

02:48:58.300 | - Yeah. - Yeah.

02:48:59.700 | Pretty amazing time.

02:49:00.940 | - But still, there's humans, so we'll see.

02:49:03.140 | We'll see if that's around 100 years.

02:49:05.180 | Maybe it'll be cyborgs and robots.

02:49:07.260 | - I think we're pretty resilient, actually.

02:49:09.260 | - Yeah, I know.

02:49:10.100 | That's one lesson from life is it finds a way.

02:49:14.540 | Let me ask you a bigger question.

02:49:16.220 | As if those weren't big enough,

02:49:18.420 | let's look out maybe a few hundred years,

02:49:21.840 | maybe a few thousand years out.

02:49:24.020 | There's something called the Kardashev scale.

02:49:26.140 | It's a method of measuring civilization's level

02:49:28.140 | of technological advancement based on the amount

02:49:30.840 | of energy it's able to use.

02:49:32.500 | So type one civilization, and this might be,

02:49:35.420 | given all your work, is not no longer a scale

02:49:38.620 | that quite makes sense, but it very much focuses

02:49:43.020 | on the source of fusion, natural source of fusion,

02:49:46.100 | which is, for us, the sun.

02:49:48.100 | And type one civilizations are able to leverage

02:49:51.700 | sort of collect all the energy that hits Earth.

02:49:55.180 | And then type two civilizations are the ones

02:49:58.000 | that are able to leverage the entirety of the energy

02:50:02.100 | that comes from the sun by maybe building something--

02:50:04.980 | - Like a Dyson sphere. - Like a Dyson sphere.

02:50:06.800 | So when will we reach type one status?

02:50:09.580 | Is get to the level, which we're, I think,

02:50:12.420 | maybe a few orders of magnitude away from currently.

02:50:15.660 | And in general, do you think about this kind of stuff?

02:50:17.740 | Because where energy's so fundamental to,

02:50:21.060 | like, of life on Earth, but also the expansion

02:50:24.240 | of life into the universe.

02:50:25.980 | - Oh yeah, so one of the fun, on a weekend,

02:50:30.340 | when I sat down and figured out what would it mean

02:50:33.180 | for interstellar travel, like to have a DT fusion.

02:50:36.980 | In fact, one of the, I talked about my design class.

02:50:39.880 | One of my design classes was how you use,

02:50:42.540 | essentially, a special configuration of a fusion device

02:50:47.180 | for not only traveling to, but colonizing Mars.

02:50:50.640 | So, 'cause what would, you talk about energy use

02:50:53.980 | being at the heart of civilization.

02:50:55.980 | It's like, so what if you wanna go to Mars

02:50:57.780 | not to just visit it, but actually, like,

02:50:59.740 | leave people there and make something happen,

02:51:02.500 | needs massive amounts of energy.

02:51:04.580 | So what would that look like?

02:51:05.700 | And it actually transforms how you're thinking

02:51:08.340 | about doing that as well, too.

02:51:09.900 | Oh yeah, so we do all those kinds of fun.

02:51:11.860 | And actually, it was a fairly quasi-realistic, actually.

02:51:14.820 | - So do you think it'll be nuclear fusion

02:51:17.780 | that powers the civilization on Mars?

02:51:20.420 | - Well, what we considered was something,

02:51:22.280 | so it turns out that there's thorium,

02:51:25.100 | which is a heavy element, so it's a so-called

02:51:27.520 | fertile element, that we know, we still know

02:51:31.280 | fairly little about the geology of Mars

02:51:34.640 | in the deep sense, and we know that there's a lot

02:51:37.640 | of this on the surface of Mars.

02:51:39.160 | So one of the things we considered was what would happen,

02:51:41.740 | that it's basically a combination of a fusion device

02:51:45.060 | that actually makes fuel from the thorium.

02:51:48.900 | But the underlying energy one was fission itself

02:51:53.160 | as well, too.

02:51:54.000 | So this is one of the examples of trying to be clever

02:51:57.220 | right around those things.

02:51:58.060 | Or what is it, you know, this also means

02:52:00.100 | it's like interstellar travel.

02:52:01.560 | It's like, oh yeah, that looks almost like impossible,

02:52:03.840 | basically, from an energy balance point of view,

02:52:06.120 | just 'cause the energy required that you have to transport

02:52:09.740 | to get there, almost the only things that would work

02:52:12.480 | are DT fusion and basically annihilation.

02:52:16.880 | It's like Star Trek, right?

02:52:18.400 | - That's what it is.

02:52:19.240 | - So your sense is that interstellar travel

02:52:22.380 | will require fusion power.

02:52:24.580 | - Oh, it's almost even impossible with fusion power,

02:52:27.380 | actually, it's so hard.

02:52:29.420 | It's so hard, because you have to carry the fuel with you,

02:52:33.480 | and the rocket equation tells you about how much fuel

02:52:35.920 | you'll use to take, so what you end up with is like,

02:52:39.440 | how long does it take to go to these places?

02:52:41.480 | And it's like staggering, you know, periods of time.

02:52:44.900 | - So I tend to believe that there's alien civilizations

02:52:48.120 | dispersed all throughout the universe.

02:52:50.040 | - Yeah, but we might be totally isolated from them.

02:52:52.840 | - So you think there's none in this galaxy?

02:52:55.280 | So like, and I guess, and the question I also have

02:52:58.840 | is what kind of, do you think they have nuclear fusion?

02:53:01.960 | 'Cause like, is the physics all the same?

02:53:04.040 | - Yeah, oh, the physics is all the same, yeah, right.

02:53:06.120 | So this is the, and this is the Fermi paradox,

02:53:08.280 | like where the hell is everybody in the universe?

02:53:10.880 | Well, there's some, you know, the scariest one of those

02:53:15.160 | is that, I would point out that there's been, you know,

02:53:18.360 | there's, you know, order of many tens of millions

02:53:21.520 | of species on the planet Earth, and only one ever got

02:53:25.160 | to the point of sophisticated tool use,

02:53:28.080 | that we could actually start essentially leveraging

02:53:31.120 | the power of what's in nature to our own will.

02:53:35.480 | Does this mean that basically this means,

02:53:37.520 | so almost, look, there is almost certainly life

02:53:40.200 | or DNA equivalents or whatever would be somewhere,

02:53:43.160 | I mean, just 'cause you just need a soup

02:53:45.000 | and you need energy and you get organics

02:53:47.880 | and whatever the equivalent of amino acids are,

02:53:50.920 | but you know, most of the life on Earth has been that,

02:53:53.080 | those are still amazing, but it's still,

02:53:55.080 | like, it's not very interesting.

02:53:57.280 | Are we actually the accident of history?

02:53:59.680 | This is a very interesting one.

02:54:00.960 | - Super, super rare accident.

02:54:03.040 | - Super rare, and then of course the other part

02:54:05.400 | is that also just the other scary part of it,

02:54:08.920 | which if you look at the Fermi paradox is,

02:54:11.480 | good, we got to this point, how long has it been

02:54:15.160 | in humans, so humans, Homo sapien has been around

02:54:18.040 | for whatever, 100,000 years, 200,000 years, something like that.

02:54:21.760 | Our ability in that timeline to actually make an imprint

02:54:25.800 | on the universe by emitting radio waves

02:54:28.600 | or by modifying nature in a significant way

02:54:32.240 | has only been for about 100 of those 100,000 years.

02:54:35.840 | And are we, it's a good question, so is it by definition,

02:54:40.680 | by the fact that when you are able to reach that level

02:54:43.880 | of being able to manipulate nature, for example,

02:54:47.000 | discover, you know, discover like fission

02:54:51.120 | or burning fossil fuels and all this,

02:54:55.840 | is that what it says, oh, you're doomed,

02:54:57.800 | because by definition, any species that gets to that point

02:55:01.400 | that can modify their environment like that,

02:55:03.760 | they'll actually push themselves past,

02:55:06.880 | that's one of the most depressing scenarios

02:55:08.520 | that I can imagine.

02:55:09.360 | - Yeah, so the--

02:55:10.200 | - So basically, we will never line up in time,

02:55:13.640 | 'cause you get this little teeny window in time

02:55:15.760 | where civilization might occur and you can never see it,

02:55:19.120 | because you never, these sort of like scatter,

02:55:22.320 | like fireflies around the galaxy and you never, yeah.

02:55:25.400 | - Goes up, goes up, goes up, goes up,

02:55:26.960 | and then explodes, destroys itself

02:55:28.820 | because of the exponential--

02:55:30.320 | - And when we say destroy ourselves,

02:55:31.640 | all we'd have to do is that we basically go,

02:55:34.080 | if humans are all left and we're still living on the planet,

02:55:38.160 | but all we have to do is go to the technology of like 1800

02:55:43.160 | and we're invisible in the universe again.

02:55:45.600 | So it was, when I listened to the,

02:55:49.200 | I thought I wanted to talk about this as well too,

02:55:51.040 | because it comes from, well, it comes from a science point

02:55:53.320 | view actually of what it means, but also to me,

02:55:55.920 | it's like another compelling driver of telling us

02:55:58.360 | it's like why we should try really hard

02:56:00.780 | not to screw this up.

02:56:02.540 | Like we're in this unique place of our ability

02:56:05.340 | to discover and to make it, and I just don't want

02:56:08.600 | to give up about thinking that we can get through.

02:56:11.080 | - Yeah, I tend to see that there's some kind

02:56:13.280 | of game theoretic force, like with mutually assured

02:56:15.640 | destruction, that ultimately in each human being

02:56:19.360 | there's a desire to survive and a willingness to cooperate,

02:56:24.360 | to have compassion for each other in order to survive,

02:56:27.800 | and I think that, I mean, maybe not in humans,

02:56:32.000 | but I can imagine a nearly infinite number of species

02:56:35.000 | in which that overpowers any technological advancement

02:56:40.000 | that can destroy or rewind the species.

02:56:43.800 | So I think if humans fail, I hope they don't.

02:56:48.320 | I see a lot of evidence for them not,

02:56:50.040 | but it seems like somebody will survive.

02:56:52.280 | And there you start to ask questions about why,

02:56:54.760 | why we haven't met yet.

02:56:56.320 | Maybe it's just space is large.

02:56:58.200 | - Oh, space is, it's, I think in logarithms,

02:57:02.240 | and I can't even fathom space.

02:57:05.240 | This is extraordinary, right?

02:57:07.520 | - Yeah.

02:57:08.360 | - It's extraordinarily large.

02:57:10.000 | - I mean, there's so many places on Earth.

02:57:11.420 | I just recently visited Paris for the first time,

02:57:14.000 | and there's so many other places I haven't visited yet.

02:57:15.560 | - There's so many other places.

02:57:16.640 | Well, I like to, you know, it's interesting

02:57:19.120 | that we have this fascination with alien life.

02:57:22.140 | We have what is essentially alien life on Earth already.

02:57:25.960 | Like, you think about the organisms that develop

02:57:28.800 | around deep sea, like thermal vents.

02:57:31.080 | One of my favorite books of all time from Stephen Jay Gould,

02:57:34.680 | if you've never read that book, it kind of blows your mind.

02:57:37.800 | It's about the Cambrian explosion of life,

02:57:40.360 | and it's like, oh, you look at these things,

02:57:42.500 | and it's like, the chance of us existing as a species,

02:57:46.320 | like the genetic diversity was larger back then.

02:57:50.280 | You know, this is about 500 million years ago

02:57:52.520 | or something like that.

02:57:53.640 | It is a mind-altering trip of thinking about our place

02:57:57.480 | in the universe, I have to say.

02:57:58.800 | - Plus the mind itself.

02:58:00.520 | - Yeah.

02:58:01.360 | - Is a kind of alien, almost a mystery to ourselves.

02:58:06.280 | We still don't understand it.

02:58:07.360 | The very mechanism that helps us explore the world

02:58:10.600 | is still a mystery.

02:58:11.840 | - Yeah.

02:58:12.680 | - So that, like understanding that will also unlock,

02:58:16.280 | quite possibly unlock our ability to understand the world,

02:58:21.280 | and maybe build machines that help us understand the world,

02:58:23.440 | build tools that--

02:58:24.440 | - Yeah, I mean, it already has.

02:58:25.800 | I mean, our ability to understand the world

02:58:27.840 | is ridiculous almost, actually.

02:58:30.740 | (laughing)

02:58:32.840 | - And post the bottom on TikTok.

02:58:34.440 | - It's almost unbelievable,

02:58:35.640 | like where we've gotten all this to, yeah.

02:58:38.080 | - So what advice would you give to young folks,

02:58:42.520 | or folks of all ages who are lost in this world,

02:58:44.960 | looking for a way, looking for a career

02:58:46.960 | they can be proud of, or looking to have a life

02:58:49.680 | they can be proud of?

02:58:50.520 | - Yeah, oh, the first thing I would say is don't give up.

02:58:53.440 | I get to see multiple sides of this,

02:58:55.980 | and there seems to be a level of despair

02:59:00.980 | in a young generation.

02:59:03.180 | It's like, no, it's almost like the Monty Python skit,

02:59:07.280 | like, I'm not dead yet, right?

02:59:08.840 | I mean, like, we're not there.

02:59:11.360 | We're in a place that, you know,

02:59:13.560 | don't say the world's gonna end in 300 days or something.

02:59:18.760 | It's not, okay?

02:59:20.000 | And what we mean by this is that we have a robust society

02:59:24.080 | that's figured out how to do amazing things,

02:59:26.380 | and we're gonna keep doing amazing things.

02:59:28.720 | But that shouldn't be complacency about what our future is,

02:59:32.760 | and the future for their children as well, too.

02:59:35.720 | And in the end, I mean, it's a staggering legacy

02:59:39.440 | to think of what we've built up,

02:59:41.460 | primarily by basically using carbon fuels.

02:59:43.660 | Like, people almost tend to think of this

02:59:45.340 | as an evil thing that we've done.

02:59:47.120 | I think it's an amazing thing that we've done,

02:59:49.620 | but we owe it to ourselves,

02:59:51.700 | and to this thing that we've built.

02:59:54.580 | I mean, we've talked about the end of the world,

02:59:55.660 | it's just nonsense.

02:59:56.820 | What it is is it's the end of this kind of lifestyle,

03:00:00.380 | and civilization at this scale,

03:00:02.940 | and the ability to execute on these kinds of things

03:00:05.220 | that we are talking about today.

03:00:06.940 | Like, we are extraordinarily privileged.

03:00:09.540 | We are in a place where it's just,

03:00:12.140 | it's almost unfathomable compared to most of the misery

03:00:15.400 | that humans have lived in for our history.

03:00:17.340 | So don't give up about this, okay?

03:00:19.740 | But also roll up your sleeves,

03:00:21.900 | and let's get going at solving,

03:00:23.780 | at getting real solutions to the problems

03:00:25.820 | that are in front of us, which are significant.

03:00:28.260 | You know, it's, I would argue,

03:00:30.140 | most of them are linked to what we use in energy,

03:00:33.380 | but it's not just that.

03:00:34.500 | It's around all the aspects of, like, what does it mean,

03:00:38.300 | like, what does it mean to have a distributed energy source

03:00:41.100 | that lifts billions of people out of poverty,

03:00:43.580 | you know, particularly outside of, like,

03:00:45.220 | the Western nations, right?

03:00:46.980 | That seems to me a pretty compelling, you know,

03:00:50.140 | moral goal for all of us,

03:00:53.820 | but particularly for this upcoming generation.

03:00:57.500 | And then the other part is that we've got

03:01:00.020 | possible solutions in front of us.

03:01:02.320 | Apply your talents in a way that you're passionate about

03:01:07.320 | and is gonna make a difference.

03:01:09.800 | - And that's only possible with optimism,

03:01:13.460 | hope, and hard work.

03:01:14.860 | - Yeah.

03:01:15.820 | - What, easy question.

03:01:17.920 | Certainly easier than nuclear fusion.

03:01:21.420 | What's the meaning of life?

03:01:22.560 | Why are we here?

03:01:23.820 | - 42.

03:01:25.020 | - Is it 42?

03:01:25.860 | - No, no.

03:01:26.680 | - We already discussed about the beauty of physics,

03:01:30.300 | that there's almost a desire to ask a why question

03:01:32.260 | about why the parameters have these values.

03:01:34.340 | - Yeah.

03:01:35.540 | It's very tempting, yeah.

03:01:37.060 | It's an interesting hole to go down as a scientist,

03:01:41.580 | 'cause we're a part of what people have a hard time,

03:01:45.700 | people who aren't scientists have a hard time

03:01:47.540 | understanding what scientists do to themselves.

03:01:49.940 | And a great scientist does a very non-intuitive

03:01:53.540 | or non-human thing.

03:01:54.980 | What we do is we train ourselves to doubt ourselves,

03:01:57.580 | like how, like that's a great scientist.

03:01:59.860 | We doubt everything we see,

03:02:01.660 | we doubt everything that we think,

03:02:03.380 | because we basically try to turn off the belief valve,

03:02:08.380 | right, that humans just naturally have.

03:02:12.100 | So when it comes to these things,

03:02:14.980 | like I can make my own comments to this,

03:02:17.260 | it's like personally, you see these things

03:02:19.780 | about the ratios of life.

03:02:20.820 | And I made a comment to it, I said,

03:02:21.940 | well, you know, a wrap my, some part of my brain

03:02:24.580 | that just goes, yeah, well, yeah,

03:02:27.140 | 'cause we're the only interesting multiverse,

03:02:29.340 | because by definition, it has to look like this.

03:02:31.900 | But I have to say, there's other times,

03:02:35.420 | I can say in the history of the whole,

03:02:37.820 | of what has happened over the last 10 years,

03:02:40.020 | there have been some pretty weird coincidences,

03:02:42.300 | like coincidences that like you look at it and just go,

03:02:45.780 | is that really, was that really a coincidence?

03:02:48.780 | Is something like pushing us towards these things?

03:02:54.260 | And it's a natural, it's a human instinct,

03:02:56.180 | because since the beginnings of humanity,

03:02:58.660 | we've always assigned human motivation and needs

03:03:03.660 | to these somewhat empirical observations.

03:03:08.740 | - And in some sense, the stories,

03:03:10.580 | before we understand the real explanations,

03:03:14.700 | the stories, the myths, serve as a good approximation

03:03:19.700 | for the thing that we're yet to understand.

03:03:21.700 | - Absolutely. - And in that sense,

03:03:23.420 | you said the antithesis to sort of scientific doubt

03:03:26.140 | is having a faith in these stories,

03:03:29.600 | they're almost silly when looked at

03:03:33.220 | from a scientific perspective,

03:03:34.780 | but just even the feelings of,

03:03:36.400 | it seems that love is a fundamental fabric

03:03:39.000 | of human condition, and what the hell is that?

03:03:42.340 | (laughing)

03:03:43.640 | - Well, actually-- - Why are we so connected

03:03:45.000 | to each other? - Again, as a physicist,

03:03:46.720 | I go, it's, you know, this is a repeatable thing

03:03:50.600 | that's due to a set of synapses

03:03:52.440 | that fire in a particular pattern and all this.

03:03:54.800 | You know, that's kind of like, okay, man,

03:03:56.400 | what a drag that is, right, to think of it this way.

03:03:59.040 | - And you can have an evolutionary biology explanation,

03:04:01.640 | but there's still a magic to it.

03:04:02.880 | - I mean, I see scientists, some of my colleagues,

03:04:05.480 | you know, do this as well, too.

03:04:07.000 | Like, what is spirituality compared to science?

03:04:10.800 | And so, my own feeling in this is that,

03:04:15.040 | you know, as a scientist, 'cause I've had the pleasure

03:04:18.600 | of being able to both understand what my predecessors did,

03:04:22.680 | but I also had the privilege of being able

03:04:24.560 | to discover things, right, as a scientist.

03:04:26.880 | And I see that, and you just,

03:04:29.960 | in just the range of our conversations,

03:04:32.520 | like, that is my, in a weird way,

03:04:35.800 | it's the awe that comes from looking at that.

03:04:39.320 | That is, if you're not in awe of the universe and nature,

03:04:43.600 | you haven't been paying attention.

03:04:45.000 | I mean, my own personal feeling is that I feel,

03:04:47.960 | if I go snorkeling on a coral reef,

03:04:53.440 | I feel more awe than I could ever feel, like in a church.

03:04:56.920 | - You kind of notice some kind of magic there.

03:04:59.960 | There's something about the way the whole darn thing

03:05:02.640 | holds together that just sort of escapes your imagination.

03:05:06.680 | And that's, to me, this thing of,

03:05:09.760 | and then we have different words,

03:05:10.880 | we call them holistic or spiritual,

03:05:13.400 | the way that it all hangs together.

03:05:15.120 | In fact, one of the interesting,

03:05:16.560 | you asked about what I think about,

03:05:18.280 | one of the craziest things that I think,

03:05:20.120 | that how does it hold together, is like our society.

03:05:23.360 | Like, how does, what?

03:05:25.400 | - Yeah.

03:05:26.240 | - Like, how, 'cause there's no way,

03:05:28.240 | like, just think of the United States.

03:05:30.000 | There's 330 million people kind of working like this engine

03:05:35.000 | about going towards making all these things happen,

03:05:38.600 | but there's like no one in charge of this, really.

03:05:41.200 | - Not really, yeah.

03:05:42.040 | - How the heck does this happen?

03:05:44.040 | It's kind of like, it's, so these things,

03:05:47.040 | these are the kinds of things mathematically

03:05:48.760 | and organization-wise that I think of,

03:05:51.800 | just because they're sort of, they're awe-inspiring.

03:05:54.520 | - And there's different ideas that would come up together,

03:05:57.760 | and we share them, and then there's teams of people

03:06:01.080 | that share different ideas, and those ideas compete.

03:06:03.160 | Like, the ideas themselves are these kinds

03:06:05.400 | of different organisms, and ultimately,

03:06:07.360 | somehow we build bridges and nuclear reactors.

03:06:10.160 | - And do those things.

03:06:11.280 | Well, I have to give a shout-out to my daughter,

03:06:13.040 | by the way, who's interesting.

03:06:14.800 | She's an applied math major, and she's amazing at math,

03:06:17.920 | and over the break, she was showing me

03:06:19.200 | she was doing research, and it's basically about

03:06:21.600 | how ideas and ethos are transmitted within a society.

03:06:27.080 | So she's building an applied math model

03:06:29.360 | that is explaining, like, she was showing me

03:06:32.080 | in this simulation, she goes, "Oh, look at this,"

03:06:34.760 | and I said, "Oh, oh, that's like how political parties

03:06:37.960 | "evolve," right?

03:06:39.360 | And even though it was a rather, quote-unquote,

03:06:41.200 | simple mathematical model, it wasn't really,

03:06:44.160 | it's like, oh, wow.

03:06:45.820 | - Well, maybe she has a chance to derive mathematically

03:06:49.840 | the answer to what's the meaning of life.

03:06:52.520 | - There we go.

03:06:53.360 | - And maybe it is indeed 42.

03:06:54.400 | - Well, Dennis, thank you so much for just doing,

03:06:59.400 | creating tools, creating systems, exploring this idea

03:07:04.200 | that's one of the most amazing magical ideas

03:07:07.120 | in all of human endeavor, which is nuclear fusion.

03:07:10.720 | I mean, that's so interesting.

03:07:12.880 | - You know, it's almost like my, one of my lifelong goals

03:07:16.240 | is to make it, it's not magic.

03:07:18.640 | It's like, it's boring as all heck.

03:07:20.440 | (laughing)

03:07:21.800 | And this means we're using it everywhere, right?

03:07:24.360 | - Yeah.

03:07:25.440 | And the magic is then built on top of it.

03:07:27.960 | Well, thank you for everything you do.

03:07:29.960 | Thank you for talking to me.

03:07:30.800 | It's a huge honor.

03:07:31.640 | This was a fascinating and amazing conversation.

03:07:33.960 | - Thank you.

03:07:35.480 | - Thanks for listening to this conversation

03:07:36.960 | with Dennis White.

03:07:38.200 | To support this podcast, please check out our sponsors

03:07:40.640 | in the description.

03:07:41.960 | And now let me leave you with some words

03:07:44.080 | from Albert Einstein.

03:07:45.400 | There are two ways to live your life.

03:07:48.720 | One is as though nothing is a miracle.

03:07:51.520 | The other is though everything's a miracle.

03:07:54.960 | Thank you for listening.

03:07:56.080 | I hope to see you next time.

03:07:58.000 | (upbeat music)

03:08:00.600 | (upbeat music)

03:08:03.200 | [BLANK_AUDIO]

Dennis Whyte: Nuclear Fusion and the Future of Energy | Lex Fridman Podcast #353

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