Dennis Whyte: Nuclear Fusion and the Future of Energy | Lex Fridman Podcast #353

Why weren't we pushing towards economic fusion and new materials and new methods of heat extraction and so forth? Because everybody Knew fusion was 40 years away, and now it's four years away.

The following is a conversation with Dennis White, nuclear physicist at mit, and the director of the MIT Plasma Science and Fusion Center. This is Alex Friedman podcast to support it. Please check out our sponsors in the description. And now, dear friends, here's Dennis White. Let's start with a big question. What is nuclear fusion?

It's the underlying process that powers the universe. So as the name implies, it fuses together or brings together two different elements, technically nuclei that come together. And if you can push them together close enough that you can trigger essentially a reaction, what happens is that the element typically changes. So this means that you change from one element to another chemical element to another. Underlying what this means is that you change the nuclear structure. This rearrangement through E MC squared releases large amounts of energy. So fusion is the fusing together of lighter elements into heavier elements. And when you go through it, you say, oh, look. So here are the initial elements, typically hydrogen. They had a particular mass, rest mass, which means just the mass with no kinetic energy. And when you look at the product afterwards, it has less rest mass. And so you go, well, how is that possible? Because you have to keep mass. But mass and energy are the same thing, which, which is what E equals MC squared means. And the. The conversion of this comes into kinetic energy, namely energy that you can use in some way. And that's what happens in the center of stars. So fusion is literally the reason life is, is viable in the universe.

So fusion is happening in our sun. And what are the elements?

The elements are hydrogen that are coming together. It goes through a process which is. Probably gets a little bit too detailed, but there's. It's a somewhat complex catalyzed process that happens in the center of stars. But in the end, stars are big balls of hydrogen. Which is the lightest, that's the simplest element, the lightest element, the most abundant element, most of the universe is hydrogen. And it's essentially a sequence through which these processes occur that you end up with helium. So those are the primary things. And the reason for this is because helium has features as a nucleus, like the interior part of the atom, that is extremely stable. And the reason for this is helium has two protons and two neutrons. These are the things that make up nuclei that make up all of us, along with electrons. And because it has two pairs, it's extremely stable. And for this reason it, when you convert the hydrogen into helium, it just wants to stay helium and it wants to release kinetic energy. So stars are basically conversion engines of hydrogen into helium. And this also tells you why you love fusion. I mean, because our. Our sun will last 10 billion years, approximately. That's how long the fuel will last.

But to do that kind of conversion, you have to have extremely high temperatures.

It is one of the criteria for doing this, but it's the easiest one to understand. Why is this? It's because effectively what this requires is that these hydrogen ions, or which is really the bare nucleus, so they have a positive charge. Everything has a positive charge of those ones. Is that to get them to trigger this reaction, they must approach within distances which are like the size of the nucleus itself. Because the nature. In fact, what it's really using is something called the strong nuclear force. There's four fundamental forces in the universe. This is the strongest one, but it has a strange property. Is that it. While it's the strongest force by far, it only has impact over distances which are the size of a nucleus. So to get put that into. What does that mean? It's a millionth of a billionth of a meter. Okay. Incredibly small distances. But because the distances are small and the particles have charge they want to push strongly apart, namely, they have repulsion that wants to push them apart. So it turns when you go through the math of this, the average velocity or energy of the particles must be very high to have any significant probability of the reactions happening. And so the center of our sun is at about 20 million degrees Celsius. And on Earth, this means it's one of the first things we teach, you know, entering graduate students. You can do a quick. You can do a quick, basically power balance. And you can. You can determine that on Earth, it requires a minimum temperature of about 50 million degrees Celsius on Earth to perform fusion, to get enough fusion that you would be able to make. Get energy gain out of it. So you can trigger fusion reactions at lower energy, but they become almost vanishingly small at lower temperatures than that.

First of all, let me just linger on some crazy ideas. So one, the strong force. Just stepping out and looking at all the physics. Is it weird to you that there's these forces and they're very particular, like it operates at a very small distance, and then gravity operates at a very large distance. And. And they're all very specific. And the standard model describes three of those forces extremely well. And there's.

This was one of them.

And yeah, this is one of Them and it's just all kind of works out. There's a. A big part of you that's, you know, an engineer that you step back and almost look at the philosophy of physics.

So it's interesting because as a scientist, I see the universe through that lens of essentially the interesting things that we do are through the forces that are. Get used around those. And everything works because of that. Richard Feynman. Had I ever read Richard Feynman? It's a little bit of a tangent.

But he's never been on the pod.

He's never been on the podcast. He was, unfortunately passed away, but one of like a. Like a hero to almost all. All physicists. And in part of it was because of what you said. He kind of looked through a different lens at these, what typically look like very dry, like, equations and relationships. And he kind of, I think he brought out the wonder of it in some sense. Right.

For.

For those. He posited what would be if you could write down a single. Not even really a sentence, but a single concept. That was the most important thing scientifically that we. That we knew about that. In other words, you had only one thing that you could transmit, like a future or past generation. It was very interesting. It was. So it's not what you think. It wasn't like, oh, strong nuclear force or fusion or something like this. And it's very profound, which was. He was that the reason that matter operates the way that it does is because all matter is made up of individual particles that interact each other through forces. That was it. So just that atomic theory, basically.

Yeah.

Which is like, wow, that's like, so simple. But it's not so simple. It's because, like, who thinks about atoms that they're made out of? Like, I. This is a good. This is a good question. I give to my students. How many atoms are in your body? Like, almost. No students can answer this, but to me, that's like a fundamental thing. By the way, it's about 10 to the 28.

28.

So that's, you know, trillion. You know, million. Trillion. Trillion or something like that. Yes.

So one thing is to think about the number, and the other is to start to really ponder the fact that.

It all holds together.

Yeah, it all holds together. And you're actually. That you're more that than you are anything else.

Yes, exactly. Yeah. No, I mean, there are people who do study such things of the fact that if you look at the. For example, the ratios between those fundamental forces, people have figured out, oh, if this ratio was different by some factor, like a factor of two or something. I was like, oh, this would all not work. And you look at the sun, right? So it turns out that there are key reactions that if they had slightly lower probability, no star would ever ignite, and then life wouldn't be possible.

It does seem like the universe set things up for us, that it's possible to do some cool things, but it's challenging. So that keeps it fun for us.

Yeah, yeah, that's the way I look at it. I mean, the, you know, the multiverse model is an interesting one because there are, you know, quantum scientists who look at figure. It's like. Oh, it's like. Oh, yeah. Like quantum science perhaps tells us that there are almost an infinite variety of other universes. But the way that it works probably is it's almost like a form of natural selection. It's like, well, the universes that didn't have the correct or interesting relationships between these forces, nothing happens in them. So almost by definition, the fact that we're having this conversation means that we're in one of the interesting ones by default.

Yeah, one of the somewhat interesting, but there's probably super interesting ones where we. I tend to think of humans as incredible creatures. Our brain is an incredible computing device, but I think we're also extremely cognitively limited. I can imagine alien civilizations that are much, much, much, much more intelligent in ways we can't even comprehend. In terms of their ability to come, to construct models of the world and to do physics. To do physics and mathematics.

I would see it in a slightly different way. It's actually, it's because we have. We have. We have creatures that live with us on the Earth that have cognition, right. That understand and move through their environment, but they. They actually see things in a way or they sense things in a way which is so fundamentally different. It's really hard. Like the, it's. It's. The problem is the translation, not necessarily intelligence. So it's the perception of the world. So I have a dog, and when. When I go and I see my dog, like, smelling things, there's a realization that I have that he sees or senses the world in a way that I can never. Like, I can't understand it because I can't translate my way to this. We get little glimpses of this as humans, though, by the way, because there are some parts of it. For example, optical information which comes from light. Is that now because we've developed the technology, we can actually see things? You know, I've had. I get this, you Know, as a. One of my areas of research is spectroscopy. So this means the study of light, you know and I, and I get this quote unquote, see things or representations of them from you know, the far infrared all the way to like hard, hard X rays which is several orders of magnitude of the, of the light intensity. But our own human eyes like see a teeny, teeny little sliver of this so that even like bees for example, see a different place than we do. So I don't. I think if you think of there's already other intelligences like around us in a way, in a limited way because of the way they can communicate. But that's like those are already baffling in many ways. Yeah.

If we just focus in on the senses, there's already a lot of diversity but there's probably things we're not even considering as possibilities. For example, whatever the heck consciousness is could actually be a door into understanding some physical phenomena we're not haven't even begun understanding. So just like you said, spectroscopy, there could be a similar kind of spectrum for consciousness that we're just like or like these dumb descendants of apes. Like walking around it sure feels like something to experience the color red, but like we don't have. It's the same as in the ancient times. You experience physics, you experience light. It's like oh, it's bright and you know.

Yeah, yeah.

And you construct kind of semi.

What's interesting, we might actually experience this faster than we thought because we might be building another, another kind of intelligence. Yeah.

And that, that intelligence will explain to us how silly we are.

There email thread going around the professors in my department already of. So what is it going to look like to figure out if students have actually written their term papers or it's chat.

The GPT.

Chat GPT it was. So as usual, as we tend to be empiricists in my field. So of course they were in there like trying to figure out if, if it could answer like questions for a qualifying exam to get into the PhD program at MIT. Which was it. They didn't do that well at that point. But of course this is just the beginning of it. So we have some interesting ones to go.

Eventually both the students and the professors will be replaced by Chad GPT.

Yeah.

And we'll sit on the beach.

I really recommend, you know this. I don't know if you've ever seen them. It's called the Day the Universe Changed this. Is that a movie? James Burke, he's a science historian based in the UK he had a. Had a fairly famous series on, on public television called Connections, I think it was. But the one that I really enjoyed was the Day the universe Changed. And the, the reason for the title of it was that it says the universe is what we know and perceive of it. So when there's a fundamental insight as to something new, the universe for us changes. Of course, the universe from an objective point of view is the same as it was before, but for us, it has changed. So he walks through these, these moments of perception in the history of humanity that like, changed what we were. Right. And so as I was thinking about coming to, to discuss this, you know, people see fusion. Oh, it's still far away, or we've been. It's been slow progress. It's like when my, when my godmother was born, like, people had no idea how stars worked. So you talk about, like that day, that insight, the universe change is like, oh, this is the. I mean, and they still didn't understand all the parts of it, but, you know, they basically got it. It's like, oh, because of the, because of the understanding of these processes. It's like we unveiled the reason that there can be life in the universe. That's probably one of those days the universe changed, right? Yeah. And that was in the 1930s.

It seems like technology is developing faster and faster and faster. I tend to think, just like with Chad GPT, I think this year might be extremely interesting just with how rapid and how profitable the efforts in artificial intelligence are that just stuff will happen where our whole world is transformed like this and there's a shock, and then next day you kind of go on and you adjust immediately. You probably won't have a similar kind of thing with nuclear fusion with energy, because there's. There's probably going to be an opening ceremony and stuff, an announcement. It'll take months. But with, with digital technology, you can just have a immediate transformation of society and then it'll be this gasp, and then you kind of adjust like we always do, and then you don't even remember, just like with the Internet and so on, how the days were before.

And how it worked before. Right. I mean, fusion will be because it's energy. Its nature is that it will be. And anything that has to do with energy use tends to be a slower transition. But they're the most, I would argue, some of the most profound transitions that we make. I mean, the reason that we can live like this and sit in this building and have this podcast and people around the world is at its Heart is energy use. And it's intense energy use that came from the evolution of starting to use intense energies at the beginning of the industrial revolution up to now it's like it's a bedrock actually of all of these. But it doesn't tend to come overnight. Yeah.

And some of the most important, some of the most amazing technology is one we don't notice because we take it for granted because it enables this whole thing. Exactly.

Which is energy, which is amazing for how fundamental it is to our society and way of life is a very poorly understood concept actually just even energy itself. People confuse energy sources with energy storage with energy transmission. These are different physical phenomena which are very important. So for example, you know, you buy an electric car and you go oh good, I have an emission free car. And ah, but it's like so, so what? Why do you say that? Well it's because if I draw the circle around the car, I have electricity and it doesn't emit any, anything. Okay. But you plug that into a grid where you follow that wire back there could be a coal power plant or a gas power plant at the end of that. Oh, really mean. So this isn't like carbon free. Oh and it's not their fault. It's just, you know, they don't like the car isn't a source of energy. The underlying source of energy was the combustion of the fuel back somewhere.

Plus there's also a story of how the raw materials are mined in which parts of the world with sort of basic respect or a deep disrespect of human rights that happens in that mining. So the whole supply chain. There's a story there that's deeper than just a particular electric car with a circle around it.

And the physics or the science of it too is the energy use that it takes to do that digging up which is also important and all that. Yeah. Anyway, so yeah, we wandered away from fusion. But yes, but it's, but it's very important actually in the context of this. Just because you know those of us who work in infusion and these other kinds of sort of disruptive energy technologies. It's, it's interesting. I do think about like what would it, what is it going to mean to society to have an energy source that is like this, that, that would be like fusion, you know, which has, which has such completely different characteristics. For example, you know, free unlimited access to the fuel. But it has technology implications. So what does this mean geopolitically? What does it mean for how we, how we distribute wealth within our Society, It's. It's very difficult to know, but probably profound.

Yeah, we're going to have to find another reason to start wars instead of resources. We're gonna.

We've done a pretty good job of that over the course of our histories. Yeah.

So we talked about the. The forces of physics and again, sticking to the philosophical before we get to the specific technical stuff. E equals MC squared, you mentioned. How amazing is that to you that energy and mass are the same. And what does that have to do with nuclear fusion?

So it has to do with everything we do. It's the fact that energy and mass are equivalent to each other. They're just. The way we usually comment to it is that they're just energy, just in different forms.

Can you intuitively understand that?

Yes, but it takes a long time. I haven't for a while, but usually often I teach the introductory class for incoming nuclear engineers. And. And so we put this up as an equation and we go through many iterations of using this to how you derive it, how you use it, and so forth. And then usually in the final exam I would give. I would basically take all the equations that I've used before and I flip it around. I basically, instead of thinking about energy is equal to mass is sort of mass is equal to energy. And I asked the question in a different way and usually about half the students don't get it. It takes a while. It's. To get that intuition. Yeah. So. So in the end, it's interesting is that this is. Is actually the source of all free energy because that energy that we're talking about is kinetic energy if it can be transformed from mass. So it turns out even. Even though we used equals MC squared, this is burning coal and, and burning gas are. And burning wood is actually still equals MC squared. The problem is that you would never know this because the relative change in the mass is. Is incredibly small, by the way, which comes back to fusion, which is that E equals MC squared. Okay, so what does this mean? It tells you that the. The amount of energy that is liberated in a particular reaction when you change mass has to do because C squared is. That's the speed of light squared.

It's a large number.

It's a very large number. And it's totally constant everywhere in the universe. Which is.

Which is another weird thing.

Which is another weird thing. And in all rest frames and the. Actually the relativity stuff gets more difficult conceptually until you get through anyway, so you go. You go to that and. And it's in what that tells you is that it's the relative. It's the relative change in the mass will tell you about the relative amount of energy that's liberated. And this is what makes fusion. And you asked about fission as well too. This is what makes them extraordinary. It's because the relative change in the mass is very large as compared to what you get like in a chemical reaction. In fact, it's about. It's about 10 million times larger. And that is at the heart of why you use something like fusion. It's because that is a fundamental of nature. Like you can't beat that. So whatever you do, if you're thinking about. And why do I care about this? Well, because mass is like the fuel, right? So this means gathering the resources that it takes to gather a fuel, to hold it together, to deal with it. The environmental impact it would have. And fusion will always have 20 million times the amount of energy release per reaction that you get of those. So this is why, you know, we consider it the ultimate, like environmentally friendly energy source is because of that.

So is it, is it correct to think of mass broadly as a kind of storage of energy? Yes, you mentioned it's environmentally friendly. So nuclear fusion is a source of energy. It's cheap, clean, safe. So easy access to fuel and virtually unlimited supply. No production of greenhouse gases, little radioactive waste produced, allegedly. Can you. Can you sort of elaborate why it's cheap, clean and safe?

I'll start with the easiest one. Cheap. It is not cheap yet because it hasn't been made at a commercial scale.

Mind flies when you're having fun. Yes.

Yeah, yeah.

But yes, not yet, but we'll talk about it.

Actually we'll. We'll come back to that because it. This is cheaper or a more technically correct term, that it's economic. That it's economically interesting is. Is really the primary challenge actually a fusion at this point. But I think we can get back to that. So what were the other ones you said?

So, so cheap. We're actually, when we're talking about cheap, we're thinking like asymptotically, like if you take it forward several hundred years, that's sort of because of how much availability there is of resources to use.

Of the fuel.

Yeah, of the fuel.

We should separate those two. The fuel will. All the fuel is already cheap. It's basically free, right? What do you mean by basically free? So if, if we were to be using fusion fuel sources to power your. And it's like that's all we had was fusion power plants around and we were doing it, the fuel cost per person or something like 10 cents a year, it's free. Okay. This is why it's hard to. In some ways I think it's hard to understand fusion because people see this and go, oh, if the fuel is free, this means the energy source is free because we're used to energy sources like this. So we, you know, we spend resources and drill to get gas or oil or we chop wood or we make coal, we find coal or these things. All right, so fusion, this is what makes fusion. And it's also, it's not an intermittent renewable energy source like wind and solar. So it's like. But this is, this makes it hard to say. So if you're saying the fuel is free, why isn't the, like, why isn't the energy source free? And it's because of the necessary technologies which must be applied to basically recreate the conditions which are in stars. In the center of stars, in fact. So there's only one natural place in the universe that fusion occur. Fusion energy occurs. That's in the center of stars. So that's going to bring a price to it depending on the, the cost and, sorry, the size and complexity of, of the technology that's needed to recreate those things.

And we'll talk about the details of. Yeah, we'll get technologies and which parts might be expensive today and which parts might be expensive in 200 years.

Exactly. It will have a revolution. I'm certain of it. So about clean. So clean is at its heart, what it does is converts, it basically converts hydrogen into it's heavier forms of hydrogen. The one, the most predominant one that we use on Earth and converts it into helium and some other products. But primarily helium is the product that's left behind. So helium safe, inert gas. You know, in fact, that's actually what our sun is doing, is eventually going to extinguish itself because it'll just make so much helium that doesn't, it doesn't do that. So in that sense, clean, because there's no, there's no emissions of, of carbon or pollutants that come directly from the combustion of the fuel itself.

And. Safe.

Safe.

Yeah, we're talking about very high temperatures.

Yeah, yeah. So this is also the counterintuitive thing. So I told you, temperatures which, like 50 million degrees or it actually tends to be more like about 100 million degrees is really what we aim for. So how can 100 million degrees be safe? And it's safe because it is. This is so much hotter than anything on Earth where Everything on Earth is at around 300 kelvin. You know, it's around a few tens of degrees Celsius. And what this means is that in order to get a medium to those temperatures, you have to completely isolate it from, from anything to do with terrestrial environment. It can have no contact, like with anything on Earth, basically. So this means what we. This is the technology that I just described is it. Fundamentally what it does is it takes this fuel and it isolates it from any terrestrial conditions so that it has no idea it's on Earth. It's not touching any object that's at room temperature, including the walls of the containment, even the, including the walls of the containment building or containment device or even air or anything like this. So. So it's that part that makes it safe in this, and there's actually another aspect to it, but that, that fundamental part makes it so safe in the mainline approach to fusion is also that it's very hot, but there's very, very few particles in at any time in the thing that would be the power plant. The actually, the more correct way to do it is you say there's very few particles per unit volume. So in a cubic centimeter and cubic meters. And so we can do this. So right now we're. Although we don't think of air really as there's atoms floating around us and there's a density because if I wave my hand, I can feel the air pushing against my face. That means we're in a fluid or a gas which is around us that has a particular number of atoms per cubic meter. Right. So it's. This actually turns out to be 10 to the 25th. So this is one with 25 zeros behind it per cubic meter. So we can figure out cubic meters about like this. Yeah, the volume of this table, like the whole volume. Okay, very good. So like fusion, there's a few of those. So fusion, like the mainstream one of fusion, like what we're working on at mit, will have a hundred thousand times less particles per unit volume than that. So this is very interesting because it's extraordinarily hot, 100 million degrees. But it's very tenuous. And what matters from the engineering and safety point of view is the amount of energy which is stored per unit volume. Because this tells you about the, the scenarios and that's what you worry about, because when those kinds of energies are released suddenly, it's like, what would be the consequences? Right. So the consequences of this are essentially zero because that's less energy content than.

Boiling water because of the low density.

Because of the low density. So if you take water is at about 100 million to a billion times more dense than this. So even though it's at much lower temperature, it's actually still it has more energy content. So for this reason, you know, one of the ways that I explain this is that if you imagine a power plant that's like powering Cambridge, Massachusetts, like if you were to which you, you wouldn't do this directly, but if you went like this on it, it actually extinguishes the fusion because it gets too cold immediately. Yeah. So that's the other one. And the other part is that it does not. And because it works by staying hot rather than a chain reaction, it can't run out of control. That's the other part of it. So by the way, this is what very much distinguishes it from fission. It's not a process that can run away from you because it's. It's basically thermally stable.

What is thermal stable mean that means.

Is that you want to run it at the optimization in temperature such that if it deviates away from that temperature, the reactivity gets lower. And the reason for this is because it's hard to keep the reactivity going. Like it's a very hard fire to keep going, basically.

Also, it doesn't, it doesn't run away from you.

It can't run away.

How difficult is the control there to keep it at that?

It varies from. From concept to concept, but in general, it's fairly. It's fairly easy to do that. And the easiest thing, it can't, it can't physically run away from you because the other part of it is that there's just, at any given time, there's a very, very small amount of fuel available to fuse anyway. So this means that that's always intrinsically limited to this. So if it, even if the power consumption of the device goes up, it just kind of burns itself out immediately. Yeah.

So you are the. Just to take a t. Another tangent. On a tangent, you're the director of MIT's Plasma Science and Fusion Center. We'll talk about, maybe you can mention some interesting aspects of the history of the center in the broader history of MIT and maybe broader history of science and engineering in the history of human civilization. But also just the link on the safety aspect.

Yeah.

You know, how do you prevent some of the amazing reactors that you're designing? How do you prevent. From destroying all of human civilization in the process? What safety protocols.

Fusion is interesting because it's not really directly Weaponizable. Because what I mean by that is that you have, you have to work very hard to make these conditions at which you can get energy gain from, from fusion. And this means that the. When we design these devices with respect to application in the energy field is that they, you know, you. While. While they will. Because they're producing large amounts of power and they will have hot things inside of them. This means that they have like a level of industrial hazard which is very similar to like you would have like in a chemical processing plant or anything like that. Any kind of energy plant actually has these as well too. But the underlying under. Underneath it core technology, like can't be directly used in a nefarious way because of the power that's being emitted. It just basically. Well, if you try to do those things, typically it just stops working.

So the safety concerns have to do with just regular things that, like equipment malfunctioning, melting of all this kind of stuff that has nothing to do with fusion necessarily.

I mean, usually what we worry about is the viability because in the end we build pretty complex objects to realize these requirements. And so what we try really hard to do is like not damage those components, but those are things which are internal to the fusion device. And this is not something that you would consider about like it would, as you say, destroy human civilization because that release of energy is just inherently limited because of the fusion process. So it doesn't say that there's zero. So you asked about the other feature of it, that it's safe. So it is. The process itself is intrinsically safe. But because it's a complex technology, you still have to take into account consideration aspects of the safety. So it produces ionizing radiation instantaneously. So you have to take care of this, which means that you shield it. You think of like your dental X rays or treatments for cancer and things like this. We always shield ourselves from this. So we get the beneficial effects, but we minimize the harmful effects of those. So there are all those aspects of it as well too. Yeah.

So we'll return to MIT's Plasma Science at Future Center. But let us linger on the destruction of human civilization. Which brings us to the topic of nuclear fission. What is that? So the process that is inside nuclear weapons and current nuclear power plants.

So it relies on the same underlying physical principle, but it's exactly the opposite, which actually the names imply. Fusion means bringing things together. Fission means splitting things apart. So fission requires the heaviest instead of the lightest and the most unstable versus the most stable elements. So this tends to be uranium or plutonium, primarily uranium. So take uranium. So uranium 235 is one of the. That this is one of the heaviest unstable elements. And what happens is that this is fission is triggered by the fact that one of these subatomic particles, the neutron, which has no electric charge, basically gets in proximity enough to this and triggers an instability effectively inside of this, what is teetering on the border of instability and basically splits it apart. And that's the fission, right, the fissioning. And so when that happens, because the products that are. And it roughly splits in two, but it's not even that. It's actually more complicated. It splits into this whole array of lighter elements and nuclei. And when that happens, there's less rest. Mass. Laugh than the original one. So it's actually the same. So it's again, it's rearrangement of the strong nuclear force that's happening, but that's the source of the energy. And so in the end it's like. So this is a famous graph that we show. Everybody is basically, it turns out every element that exists in the periodic table, all the things that make up everything. Have a. Remember you asked a good question. It was like, so should we think of mass as being the same as stored energy? Yes. So you can make a plot that basically shows the relative amount of stored energy in all of the elements that are stable and make up basically the world, okay, in the universe. And it turns out that this one has a maximum amount of stability or storage at iron. So it's kind of in the middle of the periodic table. Because this goes from, you know, this. It's roughly that. And so this, what that means is that if. If you take something heavier than iron, like uranium, which is. Which is more than twice as heavy than that, and you split apart, if somehow just magically you can just split apart as constituents and you get something that's lighter that will. Because it moves to a more stable energy state, it releases kinetic energy. That's the energy that we use. Kinetic energy, meaning the movement of things. So it's actually an energy you can do something with. And fusion sits on the other side of that because it's also moving towards iron. But it's do. It has to do it through fusion together. So this leads to some pretty profound differences. As I said, they have some underlying physics or science proximity to each other, but they're literally the opposite. So fusion. And why is this? It actually goes into practical implications of it, which is that fission could happen at room temperature. It's because there's this neutron has no electric charge and therefore it's literally room temperature neutrons that actually trigger the reaction. So this means in order to establish what's going on with it and it works by a chain reaction is that you can do this at room temperature. So Enrico Fermi did this like on a, on a university campus, University of Chicago campus. The first sustained, you know, chain reaction was done underneath a squash court with a big blocks of graphite. You know, it was still, don't get me wrong, an incredible human achievement. Right. But that's, you know, and then you think about fusion. I have to build a contraption of some kind that's going to get to 100 million degrees. Okay. Wow, that's a big difference. The other one is about the chain reaction that namely fission works by the fact that when that fission occurs it actually produces free neutrons. Free neutrons, particularly if they get slowed down to room temperature trigger can trigger other fission reactions if there's other uranium nearby or fissile materials. So this means that the way that it releases energy is that you set this up in a very careful way such that every, on average, every reaction that happens. Exactly. Releases enough neutrons and slows down that they actually make another reaction. One. Exactly one. And this means is that because each reaction releases a fixed amount of energy, you do this and then in time this looks like just a constant power output. So that's how our fission power plan works.

And so there's control of the chain reactions is extremely difficult and extremely important.

For it's very important. And when you intentionally design it that it creates more than one fission reaction per per starting reaction that it exponentiates away. But which is. Which is what a nuclear weapon is.

Yeah. So how does an atomic weapon work? How does a hydrogen bomb work? Asking for a friend.

Yeah, yeah. So at its heart what it ha. What you do is you very quickly put together enough of these materials that can undergo fission with room temperature neutrons and you put them together fast enough that what happens is that this process can essentially grow mathematically like very fast. And so this releases large amounts of energy. So that's the underlying reason that it works. So you've heard of a fusion weapon. So this is interesting is that it is. But it's dislike fusion energy in the sense that what happens is that you're using fusion reactions to. But it's simply. It increases the gain actually of the weapon rather than it's. It's not a pure. At its heart it's still a fission weapon. You're just using fusion reactions as a sort of intermediate catalyst basically to me, to get even more energy out of it. But it's not directly applicable to be used in an energy source.

Does it terrify you just again, to step back at the philosophical that humans have been able to use physics and engineering to create such powerful weapons?

I wouldn't say terrify. I mean, we should be. This is the, this is the progress of human. Every time that we've gotten access, you talking, you know, the day the universe changed, those really changed when we got access to new kinds of energy sources. But every time you get access, and typically what this meant was you get access to more intense energy. Right, That's. And that's what that was. And so the ability to move from burning wood to using coal to using gasoline and petroleum and then finally to use this is that, is that both the potency and the consequences are elevated around those things.

It's just like you said, the way that fusion, nuclear fusion would change the world. I don't think unless we think really deeply, we'll be able to anticipate some of the things we can create. There's going to be a lot of amazing stuff, but then that amazing stuff is going to enable more amazing stuff and more unfortunately, or depending how you see on it, more powerful weapons.

Well, yeah, but see, that's the thing. Fusion breaks that trend in the following way. So one of them. So fusion doesn't work on a chain reaction. There's no chain reaction. Zero. So this means it cannot physically exponentiate away on you because it works. And actually this is why star, by the way, we know this already. It's why stars are so stable, why most stars and suns are so stable. It's because they are regulated through their own temperature and their heating. Because what's happening is not that there's some probability of this exponentiating away, is that the energy that's being released by fusion basically is keeping the fire hot. And these tend to be, you know, and when it comes down to thermodynamics and things like this, there's a reason. For example, it's pretty easy to keep a constant temperature like in an oven and things like this. It's the same thing in fusion. So this is actually one of the features that I would argue fusion breaks the breaks. The trend of this is that it's. It has more energy intensity than fission on paper, but it actually does not have the consequences of control and sort of rapid release of the energy because it's actually the physical System just doesn't want to do that.

Yeah, we're going to have to look elsewhere for the weapons with which we fight World War Three. Fair enough. So what is plasma that you may or may have not mentioned? You mentioned ions and electrons. So what is plasma? What is the role of plasma? Nuclear fusion.

So plasma is a phase of matter or state of matter. So unfortunately our schools don't. It's like, I'm not sure why this is the case, but all children learn the three phases of matter. Right. And what does this mean? So we'll take water as an example. So if you, if it's cold, it's ice, it's in a solid phase, right. And then if you heat it up, the temp, it's the temperature that typically depends, sets the phase, although it's not, it's not only temperature. So you heat it up and you go to a liquid and obviously it changes its physical properties because it can, you can pour it and so forth, right. And then if you heat this up enough, it turns into a gas. And a gas behaves differently because there's a very sudden change in the density. Actually, that's what's. What's happening. So it changes by about a factor of 10,000 in density from the, from the liquid phase into when you make it into steam and atmospheric pressure. All very good, except the problem is they forgot like, what happens if you just keep elevating the temperature.

You don't want to give kids ideas. They're going to start experimenting and they're going to start heating up the gas.

It's good to start doing anyway. So you, it turns out that once you get above it's approximately 5 or 10,000 degrees Celsius, then you hit a new phase of matter. And actually that's the phase of matter that is for all, pretty much all the temperatures that are above that as well, too. And so what does that mean? So it actually changes phase. So it's a different state of matter. And the reason that it becomes a different state of matter is that it's hot enough that what happens is that the atoms that make up go back to Feynman, right? Everything's made up of these individual things, these atoms. But atoms can actually themselves be, which are, which are made of nuclei which contain the positive particles in the neutrons and then the electrons, which are very, very light, very much less mass than the nucleus and that surround us, this is what makes up an atom. So a plasma is what happens when you start pulling away enough of those electrons that they're free from the ion. So almost all the atoms that make us up in this water and all that, the electrons are in tightly bound states. And basically they're extremely stable. Once you're at about 5,000 or 10,000 degrees, you start pulling off the electrons. And what this means is that now the medium that is there, its constituent particles have mostly have net charge on them. So why does that matter? It's because now this means that the particles can interact through their electric charge. In some sense they were when it was in the atom as well too. But now that they're free particles, this means that they start. It fundamentally changes the behavior. It doesn't behave like a gas. It doesn't behave like a solid or a liquid. It behaves like a plasma. Right. And so why is this, why is it disappointing that we don't speak about this? It's because 99% of the universe is in the plasma state. It's called stars. And in fact, our own sun at the center of the sun is what clearly a plasma. But actually the surface of the sun, which is around 5,500 Celsius, is also a plasma because it's hot enough. That is that in fact the things that you see, sometimes you see these pictures from the surface of the sun. Amazing. Like satellite photographs of like those big arms of things and of light coming off of the surface of the sun and solar flares. Those are plasmas.

What are some interesting ways that this forced state of matter is different than gas?

Let's go to how a gas works. Right. So the reason again, and it goes back to Feynman's brilliance in saying that this is the most important concept, the reason actually solid, liquid and gas phases work, is because the nature of the interaction between the atoms changes. And so in a gas, you can think of this as being this room. And the things, although you can't see them, is that the molecules are flying around, but then with some frequency, they basically bounce into each other. And when they bounce into each other, they exchange momentum and energy around on this. And so it turns out that the probability and the distances and the scattering of those, of what they do, it's. It's those interactions that set the about how a gas behaves. So what do you mean by this? So, for example, if I take an imaginary test particle of some kind, like I spray something into the air that's got a particular color, in fact, you can do it in liquids as well too. Like how it gradually will disperse away from you. This is, this is fundamentally set because of the way that those particles are.

Bouncing into the probabilities of those particles.

The rate that they go at and the distance that they go at and so forth. So this was figured out by Einstein and others at the beginning of the Brownian motion. All these kinds of things. These, these were set up at the beginning of the last century and was really like this great revelation. Wow. This is why matter behaves the way that it does. Like wow. So but it's really like also in liquids and in solids, like what really matters is, is. Is. Is how you're interacting with your nearest neighbor. So you think about that one. The gas particles are basically going around until they. Until they actually hit into each other, though they don't really exchange information. And it's the same in a liquid. You're kind of beside each other, but you can kind of move around in a solid. You're literally like stuck beside your neighbor. You can't move like.

Yeah.

Plasmas are. Are weird in the sense is that it's not like that. So. And it's because the particles have electric charge. This means that they can push against each other without actually being in close proximity to each other. That's not an infinitely true statement which goes. Gets a little bit more technical. But basically this means that you can start having action or exchange of information at a distance. And that's in fact the definition of a plasma that it says these have a technical name is called a Coulomb collision. It just means that it's dictated by this force which is being pushed between the charged particles. Is that the definition of a plasma is a. Is a medium in which the collective behavior is dominated by these collisions at a distance. So you can imagine then this starts to give you some strange behaviors which I could quickly talk about. Like for example, one of the most counterintuitive ones is as plasmas get more hot, as they get higher in temperature, then the collisions happen less frequently. Like what? That doesn't make any sense. When particles go faster, you think they would collide more often. But because the particles are interacting through. Interacting through their electric field, when they're going faster, they actually spend less time in the influential field of each other. And so they talk to each other less in an energy and momentum exchange point of view. Just was one of the. One of the counterintuitive aspects of plasmas.

Which is probably very relevant for nuclear fusion.

Yes, exactly.

So if I can try to summarize what a nuclear fusion reactor is supposed to do. So you have what a couple of elements, what are usually the elements, usually.

Deuterium and tritium, which are the heavy forms of hydrogen.

Hydrogen. You have those and you start heating it. And then as you start heating it. I forgot the temperature you said. But no, first. First it becomes.

Oh, first it becomes plasma, so it's a gas. And then it turns into a plasma at about 10,000 degrees.

And then. So you have a bunch of electrons and ions flying around and then you keep heating the thing. And I guess as you heat the thing, the ions hit each other rarer and rarer.

Yes.

Oh, man, that's not fun. So you have to keep heating it such that you have to keep hitting until the probability of them colliding becomes reasonably high. And so also on top of that, and sorry to interrupt, you have to prevent them from hitting the walls of the reactor.

Exactly.

Somehow.

So you asked about the definitions of the requirements for fusion. So the most famous one, or some sense, the most intuitive one, is the temperature. And the reason for that is that you can make many, many kinds of plasmas that have zero fusion going on in them. And the reason for this is that the average. So you can make a plasma at around 10,000. In fact, if you come. By the way, you're welcome to come to our laboratory at the psfc. I can show you a demonstration of a plasma that you can see with your eyes and sit at about 10,000 degrees. And you can put your hand up beside it and all this. And it's like. And nothing. There's zero fusion going on.

So you have. Sorry, what was the temperature of the plasma?

About 10,000 degrees.

You can stick your hand in.

Well, you can't stick your hand into it, but there's a glass tube. You can basically see this. Yeah. And you can put your hand on the glass tube because it's.

What's the color? Is it purple?

It's. It's purple. Yeah. Yeah, it's blue and purple. It is. It is kind of beautiful. Yeah. Plasmas are actually quite astonishing sometimes in their beauty. Actually, one of the most amazing forms of plasma is lightning, by the way, which is. Is instantaneous form of plasma that exists on Earth but immediately goes away because everything else around it's at room temperature. Yeah. So there's different requirements in this. So making a plasma takes about this. But at 10,000 degrees, even at a million degrees, there's almost no probability of the fusion reactions occurring. And this is because while the charged particles can hit into each other, if you go back to the very beginning of this, remember I said, oh, these charged particles have to get to within distances which are like this size of a nucleus because of the strong nuclear force. Well, unfortunately, as the particles get closer, this, the repulsion that comes from the charge, the Coulomb force increases like the inverse distance squared. So as they get closer, they're pushing harder and harder apart. So then it gets a little bit more exotic. Which maybe you like though, that it turns out that people understood this at the beginning of the age of, after Rutherford discovered the nucleus. It's like, oh, yeah, like, how are we going to. How is this going to work? Right. Because how do you get anything within these distances? Inquire. Extraordinary energy. And it does. And in fact, when you look at those energies, they're very, very high. But it turns out quantum physics comes to the rescue because the particles aren't actually just particles, they're also waves. This is the point of quantum. You can treat them both as waves and as particles. And it turns out if they get in close enough proximity to each other, then the particle pops through basically this energy barrier through an effect called quantum tunneling, which is really just the transposition of the fact that it's a wave so that it has a finite probability of this. It's, it's this. By the way you talk about, like, do you have a hard time like conceptualizing this? These are, this is one of them.

Quantum tunnel. Yeah.

This is like throwing a ping pong ball like at a piece of paper, and then every like, you know, 100 of them just like magically show up on the other side of the paper without seemingly breaking the paper. I mean, to use a physical analogy.

And that phenomena is important is, is critical for the function of nuclear fusion.

From all kinds of fusion. So this, this is the reason why stars can work as well too. Like, the stars would have to be much, much hotter actually to be able to. In fact, it's not clear that they would actually ignite, in fact, without this effect anyway. So we get to that. So this is why there's another requirement. It's not so you must make a plasma, but you also must get it very hot in order for the reactions to have a significant probability to actually fuse. And it actually falls effectively almost to zero for lower temperature temperatures as well too.

So there's some nice equation.

Yes.

That gets you to 50 million degrees or like.

Yeah.

Or that you said practically speaking, 100 million.

It's a really simple equation. It's the ideal gas law. Basically, almost always in the end, you've got a certain number of particle of these fusion particles in the Plasma state. They're in the plasma state, there's a certain number of particles. And if the confinement is perfect, if you put in a certain content of energy, then basically eventually they just, they come up in a temperature and they become, they, they go up, they go up to high temperature. This turns out to be, by the way, extraordinarily small amounts of energy. And you go, what? It's like I'm getting something to like 100 million degrees. That's going to take the biggest flame burner that I've ever seen. No, and the reason for this is it goes back to the energy content of this. So, yeah, you have to, there's, you have to get it to high average energy, but there's very, very few particles.

This is low density. Low density in the reactor is this.

So the way that you do this is primarily, again, this is not exactly true in all kinds of fusion, but in the, in the primary one that we work on, magnetic fusion, this is all happening in a hard vacuum. So it's like it's happening in outer space. So basically you've gotten rid of all the other particles except for these specialized. So you add them one at a time? No, actually, it's even easier than that. You, you connect a gas valve and you basically leak gas into it in a controlled fashion.

Yeah, yeah. Well, this is beautiful.

How do you get the gas cylinder?

How do you get it from hitting the walls?

Yeah. So now you've touched on the other necessary requirements. So it turns out it's not just temperature that's required. You must also confine it. So what does this mean, confine it?

And there's two types of confinement, as you mentioned. You mentioned the magnetic one.

Magnetic one. And there's another called inertial as well, too. But the general principle actually has nothing to do with in particular with what you, what the technology is that you use to confine it. It's because this goes back to the fact that the requirement in this is high temperature and thermal content. So it's like building a fire. And what this means is that if you, when you release the energy into this or apply heat to this, if it just instantly leaks out, it can never get hot. Right. So you're familiar with this is like if you've got something that you're, you're trying to apply heat to, but you're just throwing the heat away very quickly. This is why we insulate homes, by the way, and things like this. Right. It's like you don't want the heat that's coming into this room to just immediately leave, because you'll just start consuming infinite amounts of heat to try to keep it hot. So in the end, this is one of the requirements, and it actually has a name we call the energy confinement time. So this means if you release a certain amount of energy into this fuel, kind of how long you sit there and you look at your watch, how long does it take for this energy to like leave the system? So you could imagine in this room that, you know, these heaters are putting energy into the air in this room, and you waited for a day. Would all the heat have gone to outside if I open up the windows? Oh, there. That's energy confinement time. Okay, so it's the same concept as that. So this is an important one. So all fusion must have confinement. It. There's another more esoteric reason for this, which is that people often confuse temperature and energy. So what do I mean by that? So this is literally a temperature, which means that it is a system in which all the particles, every particle, has high kinetic energy and is actually in a fully relaxed state, namely that entropy has been maximized. And it gets a little bit more technical, but this means that basically it is, it is a thermal system. So it's like the air in this room is like the water. It's the water in this. These all have temperatures, which means that there's a distribution of those energies because the particles have collided so much that it's there. So we, this is distinguished from having high energy particles like what we have in like particle accelerators, like CERN and so forth. Those are high kinetic energy, but it's not a temperature. So it actually doesn't count as confinement. So we go through all of those. You have temperature. And then the other requirement, not too surprising, is actually that there has to be enough density of the fuel. Enough, but not too enough, but not too much. Yes. And so in the end, the way that there's a fancy name for it, it's called the Lawson criterion because it was, it was, it was formulated by scientists in the United Kingdom about 1956 or 1957. And this was essentially the realization of, oh, this is what it's going to take, regardless of the confinement method. These are, this is the basic. What it is actually power balances just says, oh, there's a certain amount of heat coming in which is coming from the fusion reaction itself, because the fusion reaction heats the fuel versus how fast you would lose it. And it basically summarizes, is summarized by those three parameters, which is fairly simple. So Temperature. And then the reason we say 100 million degrees is because almost always in, in for, for this kind of fusion, deuterium, tritium fusion, the minimum in the density and the confinement time product is at about 100 million. So you almost always design your device around that minimum. And then you try to get it contained well enough and you try to get enough density. So, you know, so that temperature thing sounds crazy, right? That's what we've actually achieved in the laboratory. Like our experiment here at MIT, when it ran its optimum configuration, it was at 100 million degrees, but it wasn't actually the product of the density in the confinement time wasn't sufficient that we were at a place that we were getting high net energy gain, but it was making fusion reactions. So this is the sequence that you go through, make a plasma, then you get it hot enough. And when you get it hot enough, the fusion reactions start happening so rapidly that it's overcoming the rate at which it's leaking heat to the outside world. And at some point it just becomes like a star, like a sun. And our own, our own sun and a star doesn't have anything plugged into it. It's just keeping itself hot through its own fusion reactions. In the end, that's really close to what a fusion power plant would look like.

What does it visually look like? Does it, does it look like, like you said, like purple plasma? You know.

Yeah, actually it's, it's invisible to the eye because it's so hot that it's basically emitting light in frequencies that we can't detect. It's literally, it's invisible. In fact, light goes through it, visible light goes through it. So easy that if you were to look at it, what you would see in, in our own particular configuration, what we make is in the end is a donut shaped, it's a vacuum vessel to keep the air out of it. And when you, when you turn on the plasma, it gets so hot that most of it just disappears in the visible spectrum. You can't see anything. And there's very, very cold plasma which is between 10 and 100,000 degrees, which is out in the very periphery of it, which is kind of. So the very cold plasma is allowed to interact with the kind of, has to interact with something eventually at the boundary of the vacuum vessel. And this kind of makes a little halo around it and it glows as beautiful purple light basically. And these are, that's the, that's the, that's what we can sense in the human spectrum.

I remember reading on subreddit called Shower Thoughts, which people should check out. It's just fascinating philosophical ideas that strike you while you're in the shower. And one of them was, it's lucky that fire, when it burns, communicates that it's hot using visible light, otherwise humans would be screwed. I don't know if there's a deep profound truth to that, but nevertheless, I did find it on Shower Thought subreddit.

Actually, I do have. This goes off on a bit of. You're right. This is actually, it's interesting because, you know, as a scientist, you also think about evolutionary functions and how we got like, why do we have the senses that we do? Yeah. It's an interesting question. Like why can be seen ultraviolet and we can't. Then you go, well, it's natural selection. For some reason this wasn't really particularly important to us. Right. Why can't we see in the infrared and other things can. It's like.

People that could.

It's a fascinating question. Right. Obviously there's some. There's some advantage that you have there that isn't there. And even color distinguishing right. Of something safe to ease. Not safe, whatever it would be. I actually go back to this because it's something that I tell all of my students when I'm teaching ionizing radiation and radiological safety. Whatever you say there's a cultural concern or that when people hear the word radiation. What does this mean? It literally just means light is what it means. But it's light in different parts of the spectrum. Right. And so it turns out besides the visible light that we can see here, we are immersed in almost the totality of the electromagnetic spectrum. There is visible light, there's infrared light, there is microwaves going around as that's how our cell phone works. You can't. It's way past our detection capability. But also higher energy ones which have to do with ultraviolet light. How you get a sunburn. And even X rays and things like this at small levels are continually being like from the concrete in this. In the wal walls of this hotel. There's X rays hitting our body continuously. I can bring out. We can go down to the lab at mit, can bring out a detector and show you every single room will have. Have these.

By our body, you mean the 10 to the 28 atoms?

The 10 to the 28 atoms. And they're coming in and they're interacting with those things. And those particularly the ones where the light is at higher average energy per. Per light particle. Those are the ones that can possibly have an Effect on human health. So we, we have, it's interesting, humans and all animals have evolved on Earth where we're immersed in that all the time. Yeah, there's natural sources of radiation all the time, yet we have zero ability to detect it. Like zero.

Yeah. And our ability, cognitive ability to filter it all out and not.

It would probably overwhelm us actually if we could see all of it. But my main point is, goes back to your thing about fire and self protection. And if, if these ionize. If ionizing radiation was such a critical aspect of the health of organisms on Earth, we would almost certainly have evolved methods to detect it. And we have none.

And yes, the physical world that's all around is just incredible. You're blowing my mind. Dr. Dennis White. Okay, let's. So you have experience with magnetic confinement, you have experience with inertial confinement. Most of your work has been a magnetic confinement. But let's sort of talk about the sexy recent thing for a bit of a time. There's been a breakthrough in the news that laser based inertial confinement was used by DOE's National Ignition Facility at the Lawrence Livermore National Laboratory. Can you explain this breakthrough that happened in December?

Yeah. So it goes to the set of criteria that I talked about before about getting high energy gain. So in the end, what are we after in fusion is that we basically assemble this plasma fuel in some way and we provide it a starting amount of energy. Think of lighting the fire. And what you want to do is get back like significant excess gain from the fact that the fusion is releasing the energy. Energy. So it's, it's like the equivalent of like we want to have a match, a small match, light a fire and then the fire keeps us hot. It's like this is very much like that. So as I said, we've, we've made many of the. And what do we mean by we? It's like the fusion community has pursued aspects of this through a variety of different confinement methodologies. Is that the, the key part about what happens, what was the threshold we had never gotten over before, was that if you only consider the plasma fuel, not that, not the total engineering system, but just the plasma fuel itself, we had not gotten to the point yet where basically the size of the match was, was smaller than the amount of energy that we got from the fusion.

Is there a good term for when the output is greater than the input?

Yes, yes, there is. Well, there's several special definitions of this. So one of them is that if you, if you like, in a fire if you light a match and you have it there and it's an infinitesimal amount of energy compared to what you're getting out of the fire, we call this ignition, which makes sense, right? This is like what our own sun is as well too. So that was not ignition in that sense as well too. So what we call this is scientific. The one that I just talked about, which is for some instance, when I get enough fusion energy released compared to the size of the match, we call this scientific break even. Break even, Break even. And it's because you've gotten past the fact that this is unity.

Now at this point, what is fusion gain or as using the notation Q from the paper overview of the spark talking about before talk, using just the same kind of term.

Yeah, actually, so that, sorry, the technical term is Q capital Q. Oh, so.

People actually use Q.

We actually use capital Q. Or some days it's called Q is taken Q sub P or something like this. Okay, so this is which, which means, what it means is that it's in the plasma. So all we're considering is the energy balance or gain that comes from the plasma itself. We're not considering the technologies which are around it, which are providing the containment and so forth. So why, why the excitement and so? Well, because for one reason, it's a rather simple, it's a rather simple threshold to get over, to understand that you're getting more energy out from the fusion, even a theoretical sense, than you were from the starting match.

Do you mean conceptually simple?

It's conceptually simple that you get past one, that everyone, when you're less than one, that's much less interesting than getting.

Past one because there's a really big.

But it really is a scientific threshold because what QP actually denotes is the relative amount of self heating that's happening in the, in the plasma. So what I mean by this is that in the end, in these systems and what, what you want is something that, where the, the relative amount of, of heating which is keeping the fuel hot is dominated by, from the fusion reactions themselves. And so it becomes, it's sort of like thinking like a bonfire is a lot more interesting physically than just holding a blowtorch to a wet log. Right. There's a lot more dynamics, it's a lot more self evolved and so forth. And what we're excited as, as scientists is that it's clear that the, in that experiment that they actually got to a point where the fusion reactions themselves were actually altering the state of the plasma. It's like Wow. I mean, we'd seen it in glimpses before in magnetic confinement at relatively small levels, but apparently it seems like in this experiment it's likely to be a dominant dominated by self heating. That's a very important. That's a very interesting.

So that makes it a self sustaining type of.

It's more self sustaining, it's more self referential system in, in a sense. And it sort of self evolves in a way. Again, it's not that it's going to evolve to a dangerous state. It's just that we want to see what happens when, when the fusion is the dominant heating source.

And we'll talk about that. But so there's also another element which is the inertial confinement. Laser based inertial confinement is kind of a little bit of an underdog. So a lot of the broad nuclear fusion community has been focused on magnetic confinement. Can you explain just how laser based inertial confinement works? So it says 192 laser beams were aligned on a deuterium tritium DT target smaller than a p. Yes. This is like. Okay, well, you know, it depends. Not all peas are made the same, but this is like throwing a perfect strike in baseball from a pitch. This is like a journalist wrote this. I think this is like. Oh, no, it's not a journalist, it's DOE Yeah, yeah.

We try to use all these analogies.

This is like throwing a perfect strike in baseball from a pitcher's mount 350 miles away from the plate.

There you go.

Department of Energy, the United States Department of Energy wrote this. Okay, can you explain.

Interesting. What the, what the lasers, what, what actually happens? Actually there's usually mass confusion about this. So, so what's going on in this form of energy? So the fuel is, is, is delivered in a discrete, the fusion fuel, the deuterium and tritium is in a discrete spherical. It's more like a bb, let's call it a bb. So it's a small one. And all the fuel that you're going to try to, to burn is basically, basically there. Okay. And it's about that size. So what's hap. So how are you going to get. And it's at literally it's like at 20 degrees above absolute zero because the deuterium and tritium are kept in, in a liquid and in solid state. Oh, wow.

So the fuel is injected not as a gas, as a solid.

It's actually. And it's very. And these are particular experiments. They can introduce one of these, you know, these targets once per day, approximately Something like that. Because it's very, it's very, it's kind of amazing technology actually that I know some of the people that worked on this back in the day is they actually make these things at a BB size of this frozen fuel. It's actually a cryogenic temperatures and they're almost like smooth to the atom level. I mean they're amazing pieces of technology. So what you do in the end is think you, what you have is a spherical assembly of this fuel like a ball. And what is the purpose of the lasers? The purpose of the lasers is to provide optical energy to the very outside of this. And what happens is the, that energy is absorbed because it's in the solid phase of matter. So it's absorbed really in the surface. And then what happens is that, when it's absorbed in something called the ablator. What does that mean? It means it goes instantly from the solid phase to the gas phase. So it becomes like a rocket engine. But you hit it like very uniformly. So all there's like rocket engines coming off the surface. Think of like an asteroid almost. There's like rockets coming off all this. So what does that do? What does a rocket do? It actually pushes by Newton's laws, right? It pushes the other thing on the other side of it equal and opposite reaction. It pushes it in. So what it does is the lasers actually don't heat. This is what was confusing people think the lasers, oh, we're going to get it to 100 million degrees. In fact, you want the exact opposite of this. What you want to do is get essentially a rocket going out like this. And then what happens is that the sphere like and this is happening in a billionth of a second or last actually this rapidly. That force like so rapidly compresses the fuel that what happens is that you're squeezing down on it. And, and, and you know, it's like what was the C BB to? That's bad. Actually B, I should have started with a basketball basket. Goes from like a basketball down to something like, like this and a billionth of a second. And when, when that, when that happens, I mean scale that in your mind. So when that happens and in this, this comes from almost from classical physics. So there's some quantum in it as well too. But basically if you can do this like very uniformly and so called adiabatically, like you're not actually heating the fuel, what happens is you get adiabatic compression such that the very center of this thing all of a sudden just spikes up in temperature because it's actually done so fast. So why is it called inertial fusion? It's because you're doing this on such fast timescales that the inertia of the hot fuel basically is still finite. So it can't, like, push itself apart before the fusion happens.

Oh, wow.

Yeah.

So how do you make it. So how do you make it so fast?

This is why you use lasers, because you're applying this energy in very, very short periods of time, like under a fraction of a billionth of a second. And so basically that. And then the force which is coming from this comes from the energy of the lasers, which. Which is basically the rocket action which does the compression.

So it's the force is the inward facing force. Force is that increasing the temperature?

No. Exponentially. You want to keep the fuel cold and just literally just ideally compress it and then in something which is at the very center of that compressed sphere, because you've compressed it so rapidly, the laws of physics basically require for it to increase in temperature. The effect is like if you know the thing. So adiabatic cooling we're actually fairly familiar with. If you take a spray can can, right, and you push the button when it. When it rapidly expands, it cools. This is the nature of a lot of cooling technology we use, actually. Well, the opposite is true that if you would take all of those particles and jam them together very fast back in, they want to heat up. And that's what happens. And then what happens is you. You basically have this very cold, compressed set of fusion fuel. And at the center of this, it goes to this hundred million degrees Celsius. And so if it gets to that 100 million degrees Celsius, the fusion fuel starts to burn. And when that fusion fuel starts to burn, it wants to heat up the other cold fuel around it, and it just basically propagates out so fast that what you would do, ideally, you would actually burn, in a fusion sense, most of the fuel that's in the pellet. So this was very exciting because what they had done was. It's clear that they propagated this. They got this what they call a hot spot. And in fact, that this heating had propagated out into the fuel. And that's the. That's the science behind inertial fusion.

So the idea behind a reactor that's based on this kind of inertial confinement is that you would, what, have a new BB every like 10 times a.

Second or something, like.

And that there's some kind of. Yeah, so there's a. Incredible device that you kind of implied that kind of has to create one of those BBs, that.

So you have to make the BBS very fast. There's reports on this, but about what, what does it mean? You know, the starting point is can you make this gain? So this was a scientific achievement primarily because.

And the rest is just engineering.

No, no, no. The rest is incredibly complicated engineering. Well, in fact, there's still physics hurdles to overcome. So. So where does this come from? And it's actually because if you want to make an energy source out of this, this had a gain of around 1.5. That, namely the fusion energy was approximately was 1.5 times the, the laser input energy.

Okay.

This is a fairly significant threshold, however, from the, from the science of what I just told you is that there's two fundamental efficiencies which come into it, which really come from physics really. One of them is hydrodynamic efficiency. What I mean by this is that it's a rocket. So this just has a fundamental efficiency built into it, which comes out to orders of like 10%. So this means, is that your, your ability to do work on the system is just limited by that. Okay. And then the other one is the efficiency of laser systems themselves, which if their wall plug efficiency is 10%, you've done spectacularly well. In fact, the wall plug efficiency of the ones using that experiments are like more like 1%. Right. So when you go through all of this, the approximate, you know, place that you're ordering this is for, for fusion power plant would be a gain of 100, not 1.5. So you still, you know, and hopefully we see experiments that keep climbing up towards higher and higher gain. But then the whole fusion power plant is a totally different thing. So it's not one, it's not one BB and one laser pulse per day. It's like 10 times, five or 10 times per second. Like, like that. Right. So you're doing it there and then, then, and then comes the other aspect. So it's making the targets, delivering them, being able to repeatedly get them to burn. And then we haven't even talked about like, how do you then get the fusion energy out? Which is mean because these things are basically micro, you know, implosions which are occurring. So this energy is coming out to some medium on the outside that you've got to figure out how to extract the energy out of this thing, how.

Do you convert that energy to electricity.

So in the end you have to basically convert it into heat in some way. So most of the, what you in the end, what fusion makes mostly is like very energetic particles from the fusion reaction. So you have to slow those down in some way and then make heat out of it. So basically, the conversion of the kinetic energy of the particles into heating some engineered material that's on the outside of.

This, and that's, from a physics perspective, is a somewhat solved problem. But from an engineering is. It's still, it's still.

Yeah, physics. I can draw the, I can show you all the equations that tell you about how it slows down and converts kinetic energy into heat and then what that heat means. You know, you can write like an ideal thermal cycle, like a Carnot cycle. So the physics of that. Yeah, great. The integrated engineering of this is a whole other thing.

I'll ask you to maybe talk about the difference between inertial magnetic. But first we'll talk about magnetic. But let me just linger on this breakthrough. You know, it's nice to have exciting things, but in a deep human sense, there's no competition in science and engineering. We're all, like you said, we were broad, first of all. We are humanity altogether. And you talk about this. It's a bunch of countries collaborating. It's really exciting. There's a nuclear fusion community broadly, but then there's also mit. There's colors and logos and it's exciting. And there's a, that you, you have friends and colleagues here that, that work extremely hard and done some incredible stuff. Is there some sort of. How do you feel seeing somebody else get a breakthrough and using a different technology? Is that exciting? Does the competitive fire get all of the above?

I mean, I mean, the ignition, you know, I have so, you know, to, you know, just to wave the, wave the flag a little bit. So MIT was a central player in, in this, in this accomplishment. Interesting. I would say it showed our two, some of our two best traits. So one of them was that the like, how do you know that this happened, this measurement? Right. So one of the ways to do this is if I told you is that the, in the DT fusion, what it actually, the product that comes out is helium. We call an alpha, but it's helium and a free neutron. Right. So the neutron contains 80% of the fusion of the energy released by the fusion reaction. And it also, because it has lack. It lacks a charge. It basically tends to just escape and go flying out. So this is what we would use eventually for that's mostly what fusion energy would be. But so what my, my colleagues, my scientific colleagues at the Plasma Science and Fusion center built were Extraordinary measurement tools of being able to see the exact details of not only the number of neutrons that were coming out, but actually what energy that they're at. And by looking at that, that configuration, it reveals enormous. I'm not going to, I'm not going to scoop them because they need to publish the paper, but it reveals enormous amounts of scientific information about what's happening in that process that I just described. So exciting. I mean, and I have, you know, I have colleagues there that have worked like for 30 years on this for that moment. Of course you're excited for them. I mean, and it's one of those, like there is, there is nothing. It's hard to describe to people who aren't. Haven't who. It's almost addicting to be a scientist when you get to be at the forefront of research of anything. Like when you see like an actual discovery of some kind and you're looking at it, particularly when you're the person who did it, right. And you go, no human being has ever seen this or understood this. It's like, it's pretty thrilling, right? So even, even in proxy, it's. It's incredibly thrilling to see this. It's not, I don't. It's rivalry or jealousy. It's like, I can tell you already, fusion is really hard. So anything that keeps pushing the needle forward is a good thing. But we also have to be realistic about what it means, you know, to making a fusion energy system. That's, that's.

And then. But that's the. I mean, these are the. Still the early steps. You maybe you can say the early leaps.

Yeah.

So let's talk about the magnetic confinement. What is, how does magnetic confinement work? What's the talkamac. Yeah. How does it all work?

So go back to that. So why Inertial confinement works on the same principle that a star works. So like what is the confinement mechanism in the star is gravity because it's its own inertia of the. Something the size of the sun basically pushes literally a force by gravity against the center. So the center is. Is very, very hot. 20 million degrees. And literally outside the sun, it's essentially zero because it's vacuum of space. How the hell does that do that? It does that by. And it's out of thermo. Like why doesn't just leak all of its heat. It doesn't leak its heat because it all is held together by the fact that it can't escape because of its own gravity. So this is why the fusion happens in the center of the sar. Like we think of the surface of the sun as being hot. That's the coldest part of the star. So of our own sun, this is about, in 5,500 degrees. A beautiful symmetry, by the way. It's like. So how do we know all this? Because we can't of course, see directly into the interior of the sun. By knowing the volume and the temperature of the surface of the sun, you know exactly how much power it's putting out. And by this, you, you know that this is coming from fusion reactions across, occurring at exactly the same rate in the middle of the Sun.

Is it possible as a small tangent to build an inertial confinement system like the Sun? Is it possible to create a sun?

It is of course possible to make a sun, although you wouldn't have stars. But it is not impossible on Earth because for the simple reason that it takes, the gravitational force is extremely weak. And so it takes something like the size of a, a star to make fusion occur in the center.

Well, I, I, I didn't mean on Earth. I mean, if you had to build like a second sun, how'd you do it?

You can't, there's not enough hydrogen around. Yeah.

So the, the limiting factor is the, the, just the hydrogen.

Yeah, I mean the, the forces that, and energy that it takes to assemble that is just mind boggling. All right, so we would do that.

To be continued.

Yeah, to be continued. So what are we doing it with? So in the one that I just described, it's like I say, so you have to replace, replace this with some force which is better than that. And so what I mean by that is it's, it's stronger than that. So what I talked about, the laser fusion, this is coming from the force which is enormous compared to gravity, like, like from the rocket action of pushing it together. So in magnetic confinement, we use another force of nature which is the electromagnetic force. And that's very, it's orders and orders of magnitude stronger than the gravitational force. And the key force that matters here is that if you have a charged particle, that, namely it's a particle that has an electric net electric charge, and it's in the proximity of a magnetic field, Then there is a force which is exerted on that particle. So it's called the Lorentz force for those who are keeping track. So that is the force that we use to replace physical containment. So this again, confused. How do you hold something at 100 million degrees? It's impossible in a physical container. This is not like, you know, it's not this plastic bottle holding in this liquid or a gas chamber. What you're doing is you're using. You're immersing the fuel in a magnetic field that basically exerts a force at a distance. This comes back again to, again, like why plazas are so strange. It's the same thing here. And if it's immersed in this magnetic field, you're not actually physically touching it, but you're making a force go onto it. So that's the. That's the inherent feature of. Of magnetic confinement. And then magnetic confinement devices are like a tokamak, are basically configurations which exploit the features of that magnetic containment. There's several features to it. One is that the stronger the strength of the magnetic field, the stronger the force. And for this reason is that if you increase the strength of magnetic fields, this means that the containment, because, namely, the force which you're pushing against it is more effective. And the other feature is that there is no force. So for those who remember magnetic fields, what are these things? They're also invisible. But, you know, if you think of a permanent magnets or your fridge magnet, there are. There are field lines which we actually designate as arrows which are going around. You sometimes see this in school when you have the, you know, the iron filings on a thing and you see the directions of the magnetic field lines or, or when you use a compass, right? So that's telling you north. Because we're living in an immersed magnetic field made by the Earth, which is at very low intensity magnetic, strong enough, we can actually see what direction is. So this is the arrow that the magnetic field is pointing. It's always pointing north. And for us is that. So an interesting feature of this force is that there is no force along the direction of the magnetic field. There's only force in the directions orthogonal to the magnetic field. So this, by the way, is a huge deal in. In a whole other discipline of plasma physics, which is like the study of, like our near atmosphere. So the study of aurora borealis, what's happening in the near atmosphere, what happens when solar flares hit the magnetic field. In fact, remember I said fusion is the reason that life is responsible in the universe. Well, you could also argue so is magnetic confinement, because the charged particles which are being emitted from. From the galaxy and from our own star would be very, very damaging to on Earth. So we get two layers of protection. One is the atmosphere itself, but the other one is the magnetic field which surrounds the Earth and basically traps these charged particles so they can't get away. It's the same. It's the same. It's the same deal.

How do you create a strong magnetic field?

Yeah, so with a giant magnet. Giant magnet, yeah. So it's basically true engineering. There's essentially. There's essentially two ways to create a magnet. So one of them is that we're familiar with, like fridge magnets and so forth. These are so called permanent magnets. And what it means is that within these, the atoms arrange in a particular way that it produces the electrons basically arrange in a particular way that it produces a permanent magnetic field that is set by the material. So those tend. Those have a fundamental limitation, how strong they can be. And they also tend to have this like circular shape like this. So we don't use. You don't typically use those. So what we use are so called electromagnets. And what is this? It's like. So the other way to make a magnetic field also go back to your, you know, your elementary school physics or science class, is that you take a nail and you wrap a copper wire around it and connect it to a battery. Then it can pick up iron filings. This is an electromagnet at its simplest. What it is, it's an electric current which is going in a pattern around and around and around. And what this does is it produces a magnetic field which goes through it by the laws of electromagnetism. So that's what an electric. That's. So that's how we make the magnetic field in these. In these configurations. And the key there is that you. It's not limited by the magnetic property of the material. The magnetic field amplitude is set by the amount of the geometry of this thing and the amount of electric current that you're putting through. And the more electric. Electric current that you put through, the more magnetic field that you get. The closest one that people maybe see is one of my. One of my favorite skits actually was Super Dave Osborne on it's probably, probably past years in a show called Bizarre. Super Dave Osborne, which was a great comedian called. He was a stuntman. And one of his tricks was that he was. He gets into a car and then one of those things in the junkyard comes down, you know, and picks up the car and then puts it into the. Into the crusher. This is his stunt, which is pretty hilarious anyway, but that thing that picks him up, like, how does that work? That's actually not a permanent magnet. It's a. It's an electromagnet. And so you can turn by turning off and on the power supply, it turns off and on the magnetic field. So this means you can pick it up and then when you switch it off, the magnetic field goes away and the car drops. Okay, so that's. That's what it looks like.

Speaking of giant magnets, MIT and Commonwealth Fusion Systems CFS built a very large, high temperature superconducting electromagnet that was ramped up to a field strength of 20 Tesla. The most powerful magnetic field of its kind ever created on Earth. Because I enjoy this kind of thing. Can you please tell me about this magnet?

Yeah, sure. Oh, it was. It's fun. Yeah, there's a lot to parse there. So maybe we. So we already explained an electromagnet, which in general is, what you do is you take electric current and you force it to follow a pattern of some kind. Typically like a circular pattern around and around and around, around it goes. The more time, the more current, and the more times it goes around, the stronger the magnetic field that you make. Okay. And as I pointed out, it's like really important in magnetic confinement because it is the. The force that's produced by that magnet. In fact, technically, it goes like the magnetic field squared, because it's a pressure which is actually being exerted on the plasma to keep it contained.

Just, just so we know for magnetic confinement, what is usually the geometry of the magnet? What do we.

The geometry? Yeah. So the geometry is typically. That typically is what you do is you want to produce a magnetic field that loops back on itself. And the reason for this was. Goes down to the nature of the force that I described, which is that there's no. There's no containment or force along the direction of the magnetic field. So here's a magnetic field. In fact, what. What it's more technically or more graphically what it's doing is that when the. When the plasma is. Here's plasma particles here, here's a magnetic field. What it does is it forces all those. Because of this, this Lorentz force, it makes all of those charged particles execute circular orbits around the magnetic field. And they go around like this, but they stream freely along the magnetic field line. So this is why the nature of the containment is that if you can get that circle smaller and smaller, it stays further away from Earth temperature materials. That's why the confinement gets better. But the problem is, is that because it free streams along, so we just have a long straight magnetic field. Okay. It'll just keep leaking out the ends, like really fast. So you get rid of the ends. So you basically Loop it back around. So what these look like are typically donut shaped or more technically toroidal shape, but donut shaped things where this collection of magnetic fields loops back on itself. And it also, for reasons which are more complicated to explain, basically it also twists, it also twists slowly around in this direction as well too. So that's what it looks like, that's what the plasma looks like, because that's what the fuel looks like. So then this means, is that the, the electromagnets are configured in such a way that it produces the desired magnetic fields around this.

So they precise does this have to be?

You were probably listening to our conversation with some of my colleagues yesterday. So it's actually, it's, it depends on the configuration about how you're doing it, the configuration of the plasma, the configuration of the electromagnets, and about how you're achieving this, this requirement. It's fairly precise, but it doesn't have to be. Particularly in something like a tokamak. What we do is we produce planar coils, which is mean they're flat and we situate them. So if you think of a circle like this, what does it produce? If you put current through it, it produces a magnetic field which goes through the circle like this. So if you align many of them like this, this, this, this, there's things online, you can go see the picture to, to, to. You keep arranging these around in a circle itself. This forces the magnetic field lines to basically just keep executing around like this. So you tend to align that one tends to re. While it requires good confine or good alignment, it's not like insane alignment because you're, you're actually exploiting the symmetry of the situation to, to help it. There's another kind of configuration of magnetic, of this kind of magnetic confinement called a stellarator, which is, we have these names for historic reasons.

Which is different than a tokamak.

It's different than a tokamak, but actually works on the same physical principle that namely in the end it produces a plasma which loops in magnetic fields which loop back on themselves. Well, but in that, in that case the totality, basically the totality of the confining magnetic field is Produced by External 3 Dimensional Magnets. So they're twisted and it turns out the precision of those is more stringent. Yeah.

So are tokamaks by far more popular for research and development currently than stellar raiders.

Of the concepts which are there, the tokamak is by far the most mature in terms of its breadth of performance. And thinking about how it would be applied in a fusion energy system. And the history of this was that many, in fact, you asked about the, if we go back to the history of the plasma fusion center, the history of fusion is that people, scientists had started to work on this in the 1950s. It was all hush, hush and you know, Cold war and all that kind of stuff. And it's like they realized, holy cow, this is like really hard. Like we actually don't really know like what we're doing in this because everything was at low temperatures. They couldn't get confinement. It was interesting. And then they declassified it. And this is one of the few places that the west and the Soviet Union actually collaborated on, was a science.

Even during the Cold war, even during.

The middle of the Cold War, it was really. And this actually perpetuates all the way till now for we, we can talk about the, the project that, that is sort of captured in now. But, and, and, and the reason they declassified it is because like everything like kind of like sucked basically, you know, about trying to make this confinement in high temperature plasma. And then the Russians, then the Soviets, right, came along with this device called a tokamak, which is a Russian acronym which basically means magnetic coils arranged in the shape of a donut. And they said, holy cow. Everyone was stuck at a meager half a million degrees or half a million degrees, which is infusion terms of zero, basically. And then they come along, they say, oh, we've actually achieved a temperature 20 times higher than everybody else. And it's actually started to make fusion reactions. And everyone just go, oh, you know, no way. It's just hype from this. It's like, there's no way because we, we failed at this. It's a great story in the history of fusion is that then. But they insisted, said no, look, you can see this from our data. It's like this thing is really hot and it seems to be working. This is, you know, late 1960s and there was a, there was a team that went from the United Kingdom's fusion development lab and they brought this very fancy, amazing new technology called a laser. And they use this laser and they shot the laser beam like through the plasma. And by looking at the scattered light that came from it, they go, basically the scattered light gets more broadened in its spectrum if it gets hotter. So you could exactly tell the temperature of this. And even though you're not physically touching the plasma, it's like, holy cow, you're right. It is like it is 10 million degrees. And so this was One of those explosions of like everyone in the world then wanted to build a tokamak because it was clearly like, wow, this is like so far ahead of everything else that we tried before. So that actually has a part of the story to MIT in the plasma infusion center was why is there a strong fusion and a major fusion program at mit? It was because we were host to the Francis Bitter Magnet Laboratory, which is also the National High Field Magnet Laboratory. Well, you can see where this goes right from this. You know, we're kind of telling the stories backwards almost. But, you know, the, the. The advent of a tokamak, along with the fact that you could make very strong magnetic fields with the technology that had been developed at that laboratory. That was the origins of sort of pushing together the physics of the, of the plasma containment and the magnet technology and put them together in a way that I would say is, you know, a very typical MIT success story. Right. We don't do just, just pure science or pure technology. We sort of set up this intersection between them. And there were several pioneers that of my. Of the. Of people at MIT like Bruno Coppi, who's a professor in the physics department, and Ron Parker, who was a professor in electrical engineering and nuclear engineering. It's like even the makeup of the people, right, has got this blends of science and engineering in them. And that's actually. Was the origin of the plow Science Infusion center was, Was doing those things. So anyway, so back to this. So why. So yes, tokamaks have been. Have achieved the highest in magnetic fusion by far. Like the, the best amounts of these, these conditions that I talked about and in fact pushed right up to the point where they were near QP of one. They just didn't quite get over one.

So can we actually just linger on the, on the collaboration across different nations? Just maybe looking at the philosophical aspect of this, even in the Cold War, there's something hopeful to me besides the energy that these giant international projects are a really powerful way to ease some of the geopolitical tension, even military conflict across nations. There's a war in Ukraine and Russia. There's a brewing tension and conflict with China. Just the world is still seeking military conflict, cold or hot. What can you say about sort of the lessons of the 20th century and these giant projects in their ability to ease some of this tension?

So it's a great question. So as I said, there was a reason because it was so hard. That was one of the reasons they declassified it. And actually they started working together in some sense on it as well too. And I think it was really. There was heuristic or altruistic aspect to this. It's like this is something that could change, you know, the future of humanity and its nature and its relationship with energy. Isn't this something that we should work on together? Right. And, and that went along in those ones and in particularly that any kind of place where you can actually have an open exchange of, of, of people who are sort of at the intellectual frontiers of your society, this is a good thing, right. Of being able to collaborate. I've, I've had the, I mean, I have, have had an amazing, you know, career. I've worked with people from. It's like hard to throw a dart at a country and on the map and not hit a country of people that I've been able to work with. How amazing is that? And, and even just getting small numbers of people to bridge the cultural and societal, Societal, you know, divides is a very important thing. Even when it's a very teeny fraction of the overall populations, it can be held up as an example of that. But it's interesting that if you look at then that continued collaboration which continues to this day, is that this actually played a major role in fact in east west relations or like Soviet west relations, is that back in the Reagan Gorbachev days, which of course were interesting in themselves of all kinds of changes happening on both sides, but still a desire to push down the stockpile of nuclear weapons and all that. Within that context, there was a very fairly significant historic event that at one of the Reagan Gorbachev summits is that they didn't get there. They couldn't figure out how to bargain to the point of some, some part of the treat. I can't remember the details of it anymore, but they needed some kind of a symbol almost to say, but we're still going to keep working, you know, towards something that's important for all of us. What did they pick? A fusion project. And that was in the mid-1980s and actually then after. So they basically signed an agreement that they would move forward to like literally collaborate on on a project whose idea would be to show large net energy gain, infusions, commercial viability and work together on that. And very soon after that, Japan joined, as did the European Union. And now that project, it evolved over a long period of time and had some interesting political ramifications to it. But in the end, this actually also had South Korea, India and China join as well too. So you're talking about a major fraction of and now Russia, of course, instead of the Soviet Union. And actually that coalition is holding together despite the obvious political, you know, turmoil that's going around on all those things. And that's a project called ITER which is in. Under construction in the south of France right now.

Can you actually look at it before we turn to the giant magnet and maybe even talk about SPARC and the stuff going all amazing stuff going on at mit. What is it or what is this international nuclear fusion megaproject being built in this in the south of France?

So its scientific purpose is a worthy one that it's essentially in any fusion device. The thing that you want to see is more and more relative amounts of self heating. And this is something that had not been seen. Although, although we had made fusion reactions and we'd seen small amounts of the self heating, we never got to a dominant. This actually goes to this QP business. Okay. The goal of ITER and it shifted around a little bit historically, but very, you know, fairly quickly became we want to get to a large amount of self heating. So this is why it has its primary feature is to get to qp of around 10 and through this. This is a way to study this plasma that has more higher levels of self determination around on it. But it also has another feature which was let's produce fusion power at a, you know, relevant scale. And, and actually they're linked together. Which actually makes sense you think about is that because the fusion power is the heating source itself. This means that they're linked together. And so ITER makes, is projected to make about 500 million watts of fusion power. So this is a significant amount like this is what you would use, you know, for powering cities.

So it's not just the research there really. It is the development of really trying to achieve scale here. So self heating and scale.

Yeah. Yes. So this, this meant then too is the, the development of an industrial base that can actually produce the technologies like the electromagnets and so forth. And to do it with it is a tokamak. It is, it is one of these. Yes, but very interesting. It also revealed limitations of this as well too.

What.

Well, it is, it's interesting is that it is clearly a. On paper and in fact in practice as well to the world the, you know, and very different political systems and you caught, you consider at least geopolitical or economic rivals or whatever you want like working towards a common cause and one that we all think is worthy is, is very like, okay, that's very satisfying. But it's also interesting to see the limitations of this. It's because, well, you've got seven, you know, chefs in the kitchen. So what is this, what does this meant in terms of the speed of the project and the ability to govern it and so forth? It's just been a challenge, honestly, around this. And this is, I mean it's very hard technically what's, what's occurring. But when you also introduce such levels of, I mean, this isn't just me saying it. There's like GAO reports from the US government. And so this is, it's hard to like steer all of this around. And what that's tended to do is make it. It's not the fastest decision making process. You know, my own personal view of it was, it was, it was interesting because you asked me, you said about the magnet and Commonwealth fusion systems. It was. I worked most of my career on ITER because when I came into the field in the early 1990s, when I completed my PhD and started to work, this was one of the most like, you can't imagine being more excited about something like we're going to change the world with this project. We're going to do these things and we just like port like an entire generation. And afterwards as well too is just poured their imagination and their creativity about making this thing work. Very good. But also, at some point though, when, you know, when it got to being another five years of delay or a decade of delay, you start asking yourself, well, is this what I want to do? Right? Am I going to wait for this? So it was a part of me starting to ask questions with my students. I was like, is there another way that we can get to this extremely worthwhile goal? But maybe, maybe it's not that, that maybe it's not that pathway. And the other part that was clearly frustrating to me because I, I'm an advocate of fusion you asked me about was I, you know, I was like, well, it's laser fusion or inertial or inertial fusion or magnetic fusion. I just want fusion energy. Okay? Because I think it's so important to the world is that. But the other thing, if that's the case, then why do we have only one attempt at it on the entire planet, which was iterf? It's like, that makes no sense to me. Right? We should have multiple attempts at this with different levels of whatever you want to think about, a technical schedule, scientific risk which are incorporated in them, and that's going to give us a better chance of actually getting to the goal line.

With that spirit, you're leading MIT's effort to design SPARC, a compact, high field DT burning Takamak. How does it work? What is it? What's the motivation? What's the design? What are the ideas behind it?

Yeah, at its heart, it's exactly the same concept as iter. So it's basically a configuration of electromagnets. It's arranged in the shape of a donut. And within that we will do. We would do the same thing that happens in all the other tokamaks and including an eater. And in this one one is that, namely you put in gas, make it into a plasma, you heat it up, it gets to about 100 million degrees. The differentiator in SPARC is that we use the actual deuterium tritium fuel. And because of the access to very high magnetic fields, it's in a very compact space. It's very, very small. What I mean by small, so it's 40 times smaller in volume than Iter, but it uses exactly the same physical principles. So this comes from the high magnetic field. So in the end, like what is. Why does this matter? What it does is it does those things and it should get to the point where it's producing over 100 million watts of fusion power. But remember, it's 40 times smaller. So ITER was 500 megawatts. Technically our design is around 150 megawatts. It's only about a factor of three difference, despite being 40 times smaller. And we see QP large order of 10 or something like this. At that, at that, at that state is very important scientifically because this is basically matches what eater is looking to do. The plasma is dominated by its own heating. That's very, very important. And it does that for about 10 seconds. And the reason it's for 10 seconds is that in terms of that, that basically allows everything to settle. In terms of the fusion in the plasma equilibrium, everything is nice and settled. So, you know, you have seen the physical state at which you would expect a power plant to operate basically for, for magnetic fusion. Like, wow, right. But it's more than that. And it's more than that, it's because about who's building it and why and how it's being financed. So that scientific pathway was made possible by the fact that we had access to a next generation of magnet technology. So to explain this real quick, why do we call it, you said it in the words, a superconducting magnet. What does this mean? Superconducting magnet means that the materials which are in the Electromagnet have no electrical resistance. Therefore, when the electric current is put into it, the current goes around unimpeded. So it could basically keep going around and around, you know, technically for infinity. And what that means or for eternity. And what that means is that the, when you energize these large electromagnets, they're, they're using basically zero electrical power to maintain them. Whereas if you would do this in a normal wire like copper, you basically make an enormous toaster oven that's consuming enormous amounts of power and getting hot, which is the problem. Problem. That was the technical breakthrough that was realized by myself and at the time my students and postdocs and colleagues at MIT was that we, we saw the advent of this new, this new superconducting material which would allow us to access much higher magnetic fields is basically a next generation of the technology. And, and it was quite disruptive to fusion that namely what it would allow that if we could, if we could get to this point where we can make the round 20 Tesla Tesla, we knew by the rules of Tokamax that this was going to be, is going to allow us to vastly shrink like the sizes of these devices. So it wouldn't take, although, although it's a worthy goal. It wouldn't take a seven nation international, you know, treaty basically to build it. You could build it with a company and a university.

So same kind of design, but now using the superconducting magnets.

Yeah. And if, in fact, if you look at, it's like it's, if you just expand the size of it, they're like, they look almost identical to each other because it's based on the, and actually that comes for a reason by the way, is that it also looks like a bigger version of the Tokamak that we ran at MIT for 20 years where we established the scientific benefits in fact of these higher magnetic fields. So that's the pathway that runs. So we say. So what does this mean? The context is different because it was made, because it's primarily being made by a private sector company spun out of MIT because the way that it raised money and the purpose of the entity which is there is to make commercial fusion power plants, not just to make a scientific experiment. This is actually why we have, that's why we have a partnership. Right. Is that our purpose at MIT is not to commercialize directly, but boy do we want to advance the technology and the science that comes along this. And that's the reason we're sort of doing it together.

So some it and Commonwealth Fusion Systems. So what's interesting to say about financing? And this seems like from a scientific perspective, maybe not an interesting topic, but it's perhaps an extremely interesting topic. I mean you can just look at the tension between SpaceX and NASA for example.

Yes.

It's just clear that there's different financing mechanisms can actually significantly accelerate the development of science and engineering.

It's great that you brought that up. We use several historic analogs and one of them is around SpaceX, which is an appropriate one because space, you know, putting things into orbit has a, just has a minimum size to it and integrated technological complexity and budget and things like this. So you know, our point when we were like talking about starting like a fusion commercialization company, people look at you like isn't this still really just a science experiment? But one of the things that we pointed to was SpaceX to say, well, tell me like 25 years ago, how many people would have voted that the leading entity on the planet to put things into orbit? So private company people would have thought you were not so. Right. It's like. And what is interesting about Space X is that it proved it's more than actually just financing. It's really the purpose of the organization. So the purpose of a, and I'm not against public finance or anything like that, but the purpose of a public entity like, like NASA correctly, you know, speaks to the political because, because the cost comes from the political, you know, assembly that is there and I guess from us eventually as well too. But its purpose wasn't about like making a commercial product. It's about fundamental discovery and so forth, which is all rich, is all really great. It's like why did, why did SpaceX, it's interesting, why did SpaceX succeed so well is because the idea was, it's like the focus that comes in, the idea that you're going to relentlessly reduce cost and increase efficiency is a drive that comes from the commercial aspect of it. Right. And this also then changes the people in the teams which are doing it as well too and in fact trickles throughout the whole thing. Because the purpose isn't while you're, while you're advancing things like it's really good that we can put things in orbit a lot more cheaply like it advances science, which is an interesting synergy. Right. And it's the same thing that we think is going to happen in fusion that namely these, this is a bootstrap effect that actually that when you start to push yourself to think about near term commercialization, it like allows the science to get in hand faster which then allows the commercialization to go faster and up we go. By the way, we've seen this also in another. Again it's a. You have to watch out with, with analogies because they only can go so far. But like biotech is another one. Like you look at the Human Genome Project which was. It's sort of like to me that's like mapping the human genome is like that we can make net energy from fusion. Like it's one of those in your drawer that you go this is a significant achievement by humanity right in the century. And there's the Human Genome Project, fully government funded. It's going to take 20, 25 years because we basically know the technology. We're just going to be really diligent, keep going and then all of a sudden what comes along, Disruptive technology. Right. You can sequence, you know, shotgun sequencing and computer recognition patterns and basically oh, I can do this 100 times faster. Like wow. Right. So that's really the, you know, to me the story about why we started, why we launched Commonwealth Fusion Systems was more than just about another source of funding which it is a different source of funding because it comes from. It's also a different purpose which is very important.

But there's also something about mechanism that creates culture. So giving power to like a. A young student, ambitious student to have a tremendous impact on the progress of nuclear fusion creates a culture that actually makes progress more aggressively. Like, like you said, when seven nations collaborate it gives more incentive to the bureaucracy to slow things down to kind of have let's have first have a discussion and certainly don't give voice to the young ambitious minds that are really pushing stuff forward. And there's something about like the private sector that rewards, encourages, inspires young minds to say in the most beautiful of ways fu to the, to the boss. Yeah, just sort of like we'll make it faster, we'll make it simpler, we'll make it better, we'll make it cheaper.

Yeah and sometimes that brashness doesn't bear out. You know that's an aspect that you just take a different risk profile as well too. But you're right, it's this, you know of the. I mean it was interesting. Our own trajectory at the fusion center was like we were pushed into this place by necessity as well too because I told you we have and we had operated for a long time a tokamak at. On the MIT campus achieve these world records like 100 million degree plasma and stuff like wow, this is fantastic. But, you know, somewhat ironically, I have to say, is that it was like, oh, but we're not. This isn't the future of fusion anymore. Like, we're not. We're just going to stop with small projects because it's too small, right? So we should need. We need to really move on to these much bigger projects because that's really the future of fusion. And so it was defunded and this basically put at risk, like, we were going to essentially lose MIT in the ecosystem, really, a fusion, both from the research, but also clearly important from the educational part of it. So we pushed back against this. We got a lifeline. We were able to go. And it was in this time scale that we basically came up with this idea. It's like, we should do this. And in the end, it was all of those. The. The people who were in the C level of the company were all literally students who got caught in that. They were PhD students at the time. So you talk about enabling another generation, it's like, yeah, there you go, right?

So Spark gave a lifeline, a lifeline gave fuel to the. The future center, mit, that it continues.

But it's way more than that. It was. It wasn't just about, like, surviving for the sake of surviving. It was like, in the end, for me, it became like this. I remember the moment you talk about these moments as a scientist, and we were just like, we were working so hard about figuring out, like, does this really. With this really work? Like, and is. It's complex. Like, does the magnet work? Does the interaction with the plasma work? Does all these things work? And it was just a grind. Push, push, push, push. And I remember the moment because I was sitting in my office in Brookline and. And there was just like, I read, like. And I was in, I don't know, whatever, the 20 or 40th slide or something into it. And it was sort of that moment, like, it just came together and I, like, I. I got. I couldn't even sit down because all. I was just like, my wife was like, why are you walking around the apartment like this? Like, I just couldn't. She. I said, it's going to work. Like, it's going to work. Like, holy. That. That moment of realization is, like, kind of amazing, but it also brings the responsibility of making it work as well.

Yeah. How do you make it work? So you mean like that magic realization that you can have this, this modern magnet technology and you can actually, like, why do we need to work with it? Or we can do it here?

Yeah, yeah. But it's interesting that ITER is that one, one of, one of the reasons that like we started with a group of six of us at MIT and then once we got some funding through the, through the establishment of the company, it became a slightly larger. But in the end we had a rather small team. Like this was like a team of order of like 20 to 25 people design Spark in like a, like about two years. Right. How does that happen? Well, we're clever, but you have to give it its due here as well too. That again, this is an aspect always of the bootstrap up. Like I go back to the human genome project. So modern day genomics would not be possible without the underlying basis that came from setting that up. It had to be there, it had to be curiosity driven public program. It's the same with iter, but because we had the tools that were there to understand iter, we also had the tools to understand Spark. So we parlayed those in an extremely powerful way to be able to tell us about what was going to happen. So these things are never simple, right? It's like people look at this, go, oh, this means we should, should we really have a public based program about fusion or should we have it all in the private? It's like, no, no, the answer is neither way. Because in all these complex technologies you have to keep pushing on all the fronts to actually get it there.

So, you know, the natural question when people hear breakthrough with the, with the inertial confinement, with the magnetic confinement is so when will we have commercial. Yeah, reactors, power plants that are actually producing electricity. What's your sense looking out into the future? When do you think you can envision a future where we have actual electricity.

Coming from nuclear fusion, partly driven by us, but other places as well too? So there's the advent. What's, you know, what's so different now than three or four years ago? Like we launched around four years ago. What's so different now is, is the advent of a very nascent but seemingly robust like commercial fusion, you know, endeavor. So it's not just Commonwealth fusion systems, there's something like 20 plus, you know, companies. There's a sector now, there's a sector. They actually, they actually have something called the Fusion Industries association, which if your viewers want to go see this, this describes the difference. And they've got this plethora of approaches. Like I haven't even even described all the approaches. I've basically described the mainline approaches, you know, and they're all at varying degrees of technical and Scientific maturity with very huge different, you know, balances between them. But what they share is that because they're going out and finding, getting funding from the private sector is that their stated goals are about getting fusion into place so that both, it meets the investors demands, which are interesting, right, and the timescales of that. But also it's like well there's going to. And why it's because it's easy. There's going to. There's this enormous push driver about getting carbon free energy sources out into the market and whoever figures those out is going to be both very, it's going to be very important geopolitically but also economically as well too. So it's a different kind of bat, I guess or a different kind of gamble that you're taking with fusion. But it's so disruptive that it's like there's, there's essentially a class of investors and teams that are ready to go after it as well too. So what do they share in this? They typically share getting after fusion on a timescale. So that could it have any relevance towards climate change? Battling climate change. And I would say this is difficult, but it's fairly easy because it's math. So what you do is you actually go to some target, like 2050 or 2060, something like this, and say I want to be blank percent of the world's market of electricity or something like that. And we know historically what it takes to evolve and distribute these kinds of technologies because every technology takes some period of time. This so called S curve, it's basically everything follows a logarithmic curve, exponential type curve, it's a straight line, a log plot. And like you look at wind, solar fission, they all follow the same thing. So it's easy. You take that curve and you go that slope and you work backwards and you go, if you don't start in the early2030s, like it's not going to have, it's not going to have a significant impact by that time. So all of them share this idea and in fact it's not just the companies. Now the US federal government has a program that was started last year that said we should be looking to try to get like the first. And what I mean by like what does it mean to start? That you've got something that's putting electricity on the grid, a pilot, what we call it. And if that can get started like in the early2030s, you know, the idea of ramping it up, you know, makes sense. It's math, right? So that's the ambition. Then the question is, and actually this is different because the government program and they vary around in this. So for example, the United Kingdom's government idea was to get the first one on by 2040 and China has ambitions probably in middle 2000-30s or maybe a little bit later. And Europe, continental Europe is a little bit, I'm not exactly sure where it is, but it's like later, it's like 2050 or 2060 because it's mostly linked to the eater timeline as well too the fusion companies, which makes sense. It's like of course they've got the most aggressive timelines. It's like we're going to map the human genome faster as well too. Right. So it's interesting about where we are and I think, you know, my, we're not all the way there, but my intuition tells me we're probably going to have a couple of cracks at it actually on that timeline. So this is where we have to be careful though. You say commercial fusion, you know, what does that mean? Commercial fusion to me means that you're actually have a known quantity about what it costs, what it costs to build and what it costs to operate. The reliability of putting energy on the grid, that's commercial fusion. So it turns out that that's not necessarily exactly the first fusion devices that put electricity on the grid because you got it, there's a learning curve to get like better and better at it. But that's probably, I would suspect the biggest hurdle is to get to the first one.

The work I've done, the work I continue to do with autonomous vehicles and semi autonomous vehicles. There's an interesting parallel there where a bunch of companies announced a deadline for themselves in 2020, 21, 22, and only a small subset of those companies have actually really pushed that forward. There's Google with Waymo or Alphabet rather and then there's Tesla with semi autonomous driving in their autopilot full self driving mode. And those are different approaches. So Tesla is achieving much, much higher scale but the sort of, the quality of the drive is semi autonomous. Right. I, I don't know if there's a metaphor and analogy here. And then there's Waymo that's focusing on very specific cities but achieving real full autonomy with actual passengers. But the scales are much smaller. So I wonder, like just like you said, there would be these kinds of similar, kind of really hard pushes.

Absolutely. So actually this is what I, it's why I'm encouraged about fusion. So fusion is still hard, everyone be clear because of the science under, underneath it of, of achieving the right conditions for the plasma basically is a, is a, is a yardstick that you have to put up against all of them. What's encouraging that I see in this and it's actually what happens when you sort of let loose the creativity of this is maybe I'll go back to first principles. So fusion is also a fairly strange. So if you think about building a coal like burning wood and coal and gas is actually not that much different from each other because they're kind of about the same physical conditions and you get the fuel and you light into the fusion is very. Remember I told you that there's this condition of the temperature which is kind of universal. But if you take the density of the fuel between magnetic fusion and inertial fusion, they're different by about a factor of 10 billion. So this and the density of fuel really matters. And actually so does the. This means the energy confinement time is also different by a factor of 10 billion as well too because it's the product of those two. So one's really dense and short lived and the other one's really long lived and actually under dense as well too. So what that means is that the way to. To the, the way to the. To get the underlying physical state is so different among these different approaches. What it lends itself to is does this mean that eventual commercial products will actually fill different needs in the energy system. So it sort of goes to your comment about I have to suspect this because anything that is high tech and it's like a really important thing in our economy tends to never find its way as one, only one manifestation. Like look at transportation as well too. We have scooters, Vespas, you know, overland trucks, cars, electric cars. Of course we have these because they meet different demands in it. So what's interesting, you know, that I find fascinating now is that we have infusion. It's going to look like that, that probably there's the. While the near term focus is on electricity production, there might even be different kinds of markets that actually make sense in some places less than others. It comes to trade offs because we haven't really talked about the engineering yet but the engineering really matters like to the, to the operation of the device. And so it could be that, you know, I suspect what we'll end up with is several different configurations which have different features which are trade offs basically in the energy market.

What do you see as the major engineering or general hurdles. Yeah, that are in the way?

Yeah. So the first one is just the cost of building a single unit. So fusion has. And it's actually interesting you talked about the, about the different models that you have. So fusion has. One of its interesting limitations is that it's very hard. It almost at some point becomes physically impossible to actually make small power units like a kilowatt a thousand watts. You know, which is like a personal home. Like you know is about a thousand was or your personal use of energy, of electricity is about like a thousand watts. This is basically impossible in for a single, you know, unit to do this. So like you're not going to have a fusion like power plant. Like is your furnace in or your electric heater in your home? And the reason for this comes from the fact that fusion relies on and being. It's not just that it's very hot. It's that the fusion power is the heating source to keep it hot. So if, if you, if you, if you go too small it basically just cannot keep it hot. That's so it's interesting is that this, so this is one of the hard parts. So this means that the individual units, you know, and it's, it varies from concept to concept but the National Academies report that came out last year sort of put the benchmark as being like probably the minimum size looks like around 50 million watts of electricity which is like enough for like a meat like a small to you know, mid sized city actually. So that is. So that's sort of like a scale challenge. And in fact it's one of the reasons why in Commonwealth and in other private sector ones like we, they try to push this down actually of trying to get to these smaller units just because it reduces the cost of it then probably obviously I would say it's an obvious one like achieving the fusion state itself and high gain is, is a hard one. But we already talked about what kind.

Of hurdle, what kind of challenge.

Well that, that's achieving the right temperature, density and energy confinement time in the fuel itself, in the plasma itself. And so some of the, so some of the, the configurations which are being chosen have, are actually have quite a ways to go. In fact I've seen those. But what their, their consideration is. Oh yes. But by our particular configuration the engineering simplicity confers like an economic advantage even if we're behind in a, in sort of in a science sense. Okay. Which is fine. That's. This is also what you get when you get an explosion in, in the private sector. You basically are distributing risks in different ways. Right. Which makes sense. All of that. Good. So what I would say is that the. The next hurdle to really overcome is. Is about making net electricity. So like we need to see a unit or several units like put. Using fusion in some way to put a meaningful amount of energy on the grid because this starts giving us real answers as to like what this is going to look like.

The full end to end.

The full end to end thing. So Commonwealth's goal is that. I'll. I'll just comment to Commonwealth because I'll take some, you know, some. I guess some credit for this is that the origins of Commonwealth were in fact, in examining that like we could see this new technology coming forward, this new superconducting material and the origins of our thought process were really around designing effectively the pilot plant or the commercial unit. It's called arc, which is actually the step forward after Sparc and that was the origins of it. So all the things that were other parts of the plant like Sparc and the magnet, we're actually all informed totally by building something that's going to put net electricity on the grid. And the timing of that we still hope is actually the early 2000s.

So Spark is the design of the Tokamak and ARC is the actual full.

Intent thing is like a thing that actually puts that energy on the grid. So Spark is named, you know, intentionally that it's like it's on for a short period of time and it doesn't have a. It has. Yeah, you know, it's the spark of the fusion, you know, revolution or something like that, I guess we could call it. Yeah. So those are, those are. So those are sort of the programmatic challenges of doing that. And you know, it's. You asked about, you talked about SpaceX. So what has evolved even in the last year or so was in fact, In March of 2022, the White House announced that it was going to start a program that kind of looks like a SpaceX analogy, that namely, wow, we've got these things in the private sector. We should leverage the private sector and the advantages of what they obtain. But also with the things like this is going to be hard and it's going to take quite a bit of financing. So why don't we set up a program where we don't really get in the way of the private sector fusion companies, but we help them finance these difficult things, which is how SpaceX basically became successful through the COTS program. Fantastic, right? And that's evolving as well too. So like the fusion ecosystem is almost unrecognizable from where it was like five years ago around those things.

How important is it for the heads of the companies that are working on nuclear fusion to have a Twitter account and to be quite. You said you don't use Twitter.

I don't use Twitter much.

I mean there is some element to, and I don't think this should be discounted. Whatever you think about figures like Jeff Bezos with Blue Origin or Elon Musk with SpaceX, there is a science communication, to put it in nice terms, that's kind of required to really educate the public and get everybody excited and sell the sexiness of it. I mean just even the videos of SpaceX just being able to kind of get everybody excited about going out to space once again. I mean there's all kinds of different ways of doing that, but I mean, I guess those companies do well, you know, is, is to advertise themselves, to really sell themselves.

It is. Yeah, well, it's like I feel like one of the reasons on this podcast and so like I, I don't have an official role in the company and one of the reasons for, for this was also that it's interesting because when you come from like you're running a company, it's, it makes sense they're promoting their own product and their own vision, which totally makes sense. But there's also a very important role for academics who have knowledge about what's going on but are sufficiently distant from it that they're not fully only self motivated just by their own, you know, projects or so forth. And for me this is, I mean we see particularly the problems of the distrust in technology and then honestly in the scientific community as well too, it will be one of the greatest tragedies. I would say that if we go through all of this and almost pull off what looks like a miracle like technologic and scientific wise, which is to make a fusion power plant and then nobody wants to use it because they feel that they don't trust the people who are doing it or the technology. So we have to get so far out ahead of this like, so I give lots of public lectures or things like this of, of accessing a larger range of people. We're not trying to hide anything. You can come and see, you know, come do tours of our laboratory. In fact, I want to set those up virtually as well too. You might look at our Plasma Science Infusion Center YouTube channel. So we are reaching out through those meetings and it's really important that we do those things. But it's also, but also then realizing, setting up the realistic expectations of what we need to do, you know, we're not there. Like we don't have commercial fusion devices yet. And you ask like what are the challenges? I'm not going to get into any deep technical questions about what the challenges are, but it is the pathway not just to make fusion work technically, but to make it economically competitive and viable. So that's actually used out in the private sector is a non trivial task and it's because of the newness of it. Like we're simultaneously trying to evolve the technology and make it economically viable at the same time. Those are two difficult coupled tasks. So my own, my own research and my own drive right now is that fantastic Commonwealth Fusion Systems is set up. We have a commercialization unit of that particular kind which is going to drive forward a token Mac. In fact I was just there. There's discussions or there's, there's dialogues going on around the world with other kinds of ones like Stellar Raiders which prefer different kinds of challenges and economic advantages. But what we have to, I know what we have to have. What we have to have is a new generation of integrated scientists, technologists and engineers that understand like how. What needs to get done to get all the way to the goal line. Because we don't, we don't have them now.

Like a multidisciplinary.

Yeah, exactly.

What's required. I mean you've spoken about, you said that fusion is quote the most multidisciplinary field you can imagine.

Yes. Yeah.

Why, why is that? What are the.

Yeah, well, because, because most of our discussion that we've had so far is really like a physics discussion really. So which, don't, don't neglect physics at the origin of this but I've already, we touched on plasma physics and nuclear physics which are basically two, you know, somewhat overlapped but independent disciplines. Then when it comes to the engineering, it's almost everything. So, so why is this. Well, let's build, let's build an electromagnet together. Okay. What is this going to take? It's going to take. It's basically electrical engineering computer. So you understand what, how it goes together, what happens. Computational engineering to model this very complex integrated thing, materials engineering. Because it's this. You're pushing materials to their limit with respect to stress and so forth. Takes cryogenic engineering, which is sort of a sub discipline but cooling things to extremely low temperatures.

It's probably some kind of chemistry thing in there too.

Well actually yeah, the. Which tends to show up in the materials and that's just one of the sub components of it. Like almost everything gets hit in this, right? So you're, and you're also in a very integrated environment because in the end, all these things, while you isolate them from each other in a physics sense, in an engineering sense, they all have to work like seamlessly together. So it's one of those, I mean, I, in my own career, I've basically done atomic physics, spectroscopy, you know, plasma physics, iron etching. So this includes material science, something called mhd if you've magneto hydrodynamics. And now all the way through, like, I, I, I'm not even sure how many different careers I've had. It's also, by the way, this is also an, a recruiting stage for like young scientists thinking to come in. Like, my comment to sign is if you're bored in fusion, you're not paying attention because there's always something interesting to go and, and do. So that's a really important part of what we're, what we're doing, which isn't new in fusion actually and in fact is in the roots of, of what we've done at mit. But holy cow, like, the proximity of possibility of commercial fusion is the new thing, you know. So my catchphrase.