Hello at the centre of the sun, this very moment, millions of tons of hydrogen have been transformed into helium,
releasing a huge amount of energy, the physical process by which this occurs is known as nuclear fusion.
And the prospects of using this miraculous property of the natural world to generate
clean power on earth has preoccupied scientists and entrepreneurs for over 60 years.
Yet despite huge international collaboration and investment,
no terrestrial nuclear fusion device has yet been able to produce more energy than it consumes.
This, notwithstanding, the progress over this period, has been immense,
and the 21st century will most likely see the first economically viable fusion power plant.
With me to discuss the past, present and future of nuclear fusion research are Dr. Justin Ball,
originally graduate medical student in theoretical physics from Wooster College and now a postdoc hopeful Valerian Chen,
additional student immersion college, also in theoretical physics, and Jason Parisi, medical student at Merton College, also in theoretical physics.
Thank you very much for joining me.
Perhaps just for laymen like myself, we could start with a description of what the basic process of nuclear fusion is.
Jason, do you fancy taking it up for us short?
So fusion is the process whereby you take very light atomic nuclei and you literally just fusion about fuse them together.
So, for example, the sun takes hydrogen nuclei and it fuses them together.
And in that process you produce energy.
It is the opposite of fission whereby in fission, instead of having two very light nuclei and fusing them together,
fission is whereby you have a very heavy, unstable nucleus and you launch a neutron at it.
The fissionable nucleus will absorb the neutrons and split into two small units and that will release energy as well.
The reason that fusion releases energy is actually because the two separate let's say, for example, I'm talking about hydrogen fusion.
The two separate hydrogen nuclei are actually heavier than the new heavier nucleus that it will create after effusions.
And because energy has to be consolidated. So the individual hydrogen lighter than the individual helium.
So that idea combined the heavier. Yes, that's ironic. Exactly.
So actually, in 1920, Francis Asten discovered that actually two hydrogen nuclei separately, but she went terroris heavier than the new helium guy.
And that means through Einstein's very famous equation, equals MC squared.
You can actually see that that difference in mass will release energy in some form.
And usually that's in the form of kinetic energy for some particle moving off.
OK, thank you. That that was very clear.
And so I guess these are two very different kinds of nuclear processes, one of which we've been able for 60 years to use for producing energy.
Novela, and could you describe to us how fish plant would differ from a from a fusion plant?
What are the main principles of efficient plants? Which are we stick to that.
So very loosely speaking, what you have in an efficient plant is a cell where you have all this fissile material,
the fuel in it, and you control the rate of reaction by putting in rods, slow it down.
So when if you didn't have the right and you just had this material decay spontaneously creating some neutrons and you create to create one in one,
each one, for example, you would care some several neutrons to come out.
And these neutrons have quite a bit of energy into other nuclei and they do decay.
So it's like a domino effect. And this runs away and you have an explosion which you don't want.
You want something controlled release of power. So what you do is you put in.
Right. So you put in like basically a wall because it's the fashionable thing to talk about.
It is designed to slow down the rate of reaction to a system that you still have.
It still runs that you still create lots of heat, but it doesn't go out of control.
And this can be done at room temperature just in the plant as it is.
Of course, its energy then boils water and drives a turbine. But everything else of that has been done since the Industrial Revolution.
That's how you create the fires. The only difference here is cool or efficient power.
Now, we fusion light years need these light elements to come close enough to join together
to make it become heavier elements and therefore release some of the energy.
And in order for them to come close enough, you need to have a lot of energy to begin with because you see, in the previous case,
these neutrons had no charge so they could approach the nucleus positively, touch and not feel any force at all.
So they don't care about the title and you just fly into the nucleus and things happen.
Now you have two protons they both have charged, both positively charged.
How are you going to get to stick together or touch others who are?
So you need a lot of energy and love, energy needs a large temperature, and if you want to reach these temperatures, in fact,
if you want to do it efficiently and power plant skills, these temperatures to be hotter than the centre of the sun.
And that's the challenge. And the great thing about fusion is that I like fission, which is quite strange.
You have all the fuel at once. So it means that if it goes, it burns all of it.
And all of the energy is released once a few years worth of energy just released at once. The Fusion.
On the other hand, you pump the fuel to gas it. So it's more like a normal way of creating energy that you start to get fuel outside.
You put it in the chamber when you need it. So when we supply, then the reaction stops and it would explode.
OK, so what I'm sensing is that with a fission power plant, you have this very unstable material that will decay.
Really heat into the challenge, which was overcome some years ago, was to control the reactions of people reacting or once.
But you're telling me that with a fusion power plant, the difficulty is to get the material hot enough for the nuclear process to happen at all.
Yes, this saying. So just what sort of temperatures are we talking about?
We said hotter than the centre of the sun. But what sort of numbers do these mean?
Yes, this is around one hundred and fifty million degrees Celsius or Fahrenheit.
Really, the scale doesn't matter too much at these insane temperatures. So the material was hydrogen material.
That's not a gas at a temperature. What was the name for?
So if you start off with the solid material, so solid hydrogen, you know, you have lots of bonds connecting the different atoms, molecules.
And then as you heat it up, eventually you start to break the inner molecule bonds to produce a liquid heated up more.
You completely break all of these bonds and you have a gas of just different molecules flying around in the air.
And then if you heat it up even more,
eventually you can break the connexion of the nuclei in your atoms with the electrons that are orbiting around your atom.
And so when the thermal energy that's in your system, so, you know,
you have all these atoms flying around when there's so much energy in the atoms flying around,
that is similar energy to how much it takes to look to liberate an electron.
Then you can get a plasma, which is a different state of matter,
where you have free flowing nuclei and you have free electrons are going their own independent ways and and functioning independently.
So the hydrogen is in a plasma state. Yes. So at these temperatures, like in the sun, the fuel is in a plasma state.
We have free electrons and free free nuclei. So it doesn't no longer make sense to talk about an individual atom.
In that sense, you have nuclei and electrons, but you no longer have gravity.
So let's talk a little bit about the history of nuclear fusion.
You mentioned that in 1920 there was this discovery of a difference in maths that the two hydrogens
sum together separately were heavier than the helium they would create when they combined.
What were the theoretical developments happened in the 20s and 30s?
Sure. So in 1920, Einstein actually figured out that there was this change in mass.
When you fusion things together that was actually a serendipitous discovery.
Wasn't was an intentional, intentional, which is always kind of fun and science that often happens.
And then I think later that year, Rutherford took that together and said, wow, actually, it's not gravity that heats up the sun.
It's not it's not meteors striking the surface. It's not definitely not chemical.
It's actually fusion that powers the sun.
Until that point of Rutherford, people felt that it was ordinary chemical reactions that we might see right now.
If there was power powering the sun, why was there this change? What paradox could be explained by it just being chemical reactions from the sun?
Yeah, that's a fascinating question. So it was actually back in the late 60s that people really started to think about how old is the sun.
One of the main reasons for that is because biologists such as Darwin were actually coming to say, actually, how old is the earth?
And looking at like they did very kind of back of the envelope calculations
just to see like how long does it take for this kind of level of complexity, like human beings or mammals or whatever, to evolve?
And they came up with like hundreds of millions of years. Now, if you take the most energetic chemical reaction you can imagine and,
you know, the mass of the sun, we people knew the mass of the sun back in 1850.
So it's pretty easy to figure out then. So you take the most energetic chemical reaction, the sun with its mass,
which is about 10 to the 30 kilograms and its current power output would only last a few thousand years, which is crazy if you think about it.
So that even the most devout Christians at the time, like Lord Kelvin, no way can it be chemical reactions that's powering it.
So there are two other key theories that people thought about.
The first was that the sun would kind of contract under its own gravity and that would heat it up and.
A little bit, and that would cause it to radiate and by continuously doing that, you would get a lifetime of about 30 million years for the sun.
And also another theory was that like loads of meteors and asteroids were kind of consistently striking the surface of the sun heating up.
And that also gave tens of billions of years. So lots of physicists were kind of satisfied with that to some extent.
Kelvin really liked the meteoric theory, for example, but biologists and geologists who were looking at rocks and how they were were not satisfied.
So there was this tension between hanging. The physics is telling us the sun is only tens of millions of years old.
But the geologists and biologists telling us the earth is at least hundreds of billions of years old.
And obviously everyone assumed that the sun has to be at least as old as the Earth.
And therefore, there was the tension. That's really interesting.
After the 1920s, people who felt that the nuclear fusion process was behind the sun, just a number, right.
That in the 1930s there was more progress made about the actual details of the nuclear processes.
Yeah, that's correct. So there is a famous paper by Hans-Peter where he laid out all of the detailed fusion reactions that were going on.
So from starting with just using normal hydrogen and then on to form progressively heavier elements.
Right. And so all of these processes, starting with hydrogen and ending with elements like oxygen and carbon,
were mapped out the exact process by which stars or somebodies have your elements.
Maybe we could nail down my own understanding at least.
Why is it a good idea to collide these very small elements, whereas in fission we're splitting apart very big elements.
Yeah. So it gets back to what we said earlier, that if you combine really small elements, you can produce atom,
that it weighs less than the the mass of what you initially put in to produce energy.
And so the really light elements are easiest because they have the lowest electric charge.
So basically you're trying to get these two nuclei to stick together. But the electric repulsion, you know, the positive charges repel each other.
And so the lightest elements have the lowest electric charge. So it's easiest to bring them together.
And the more stable nuclei, ironically possible because anything bigger wants to break into smaller,
smaller nuclei because the electrostatic repulsion in the nucleus is high.
Anything smaller wants to become bigger because he wants to have more other nuclear arms around it.
So so nuclear forces stabilise it. In a way, this is like groups of friends.
So when you are two people in a room, you have two of you in a room.
You need to overcome the awkwardness, which is like the repulsions. You want to find a nucleus.
If I do come close enough to have a conversation and start the bonds of friendship.
On the other hand, if the group is big, it's very difficult to coordinate things.
People get left out and so the awkwardness dominates and the group breaks up into smaller groups.
And eventually you settle on the number which you can find it by force nuclei.
It's numbers bigger. And so the same thing happens with elements that everybody wants to become.
Nicole and are the. OK, so this is free, but of course, very well documented that there was lots of nuclear research.
That was during the war, culminating in the Hiroshima and Nagasaki bombs, which were fission bombs.
But your time period is really quite interesting story about what happened after the war when people tried to use these for the military uses,
but also for power. Justin, you were telling me about this particular Argentinean scientist and this story to do with you.
Yeah, yeah. So right after the war, there is a lot of optimism of the nuclear power.
And so people knew about fusion. And immediately following the war, there is a lot of work on employing fusion in nuclear weapons.
So during the war, we reduced fission weapons that we wanted to apply it to fusion weapons.
And there wasn't initially a lot of investigation into using fusion to produce electricity for peaceful means.
But there is a famous event now where an Argentinean scientist named Ronald Richter,
um, you know, in this kind of mad scientist lab on an island in Argentina,
claimed to have achieved fusion and claimed that he was going to bring unlimited energy to the world.
And this cut the the eye of the president of Argentina who who made this grand declaration
and so naturally was picked up by all sorts of papers around the world making headlines,
which caught the attention of physicists, especially Spitzer, who is a plasma physicist working at Princeton at the time.
And so he immediately thought through so through this. And so this method wouldn't work.
But it prompted a question like, can you do this and what are what are the best ways to do it?
And so he immediately started thinking about ways to produce fusion energy.
And several years later,
founded the famous Princeton plasma physics lab and invented one of the most promising devices that we still use today called the stallholder Drayson,
this research has been done after the war. Was this done as a larger global collaboration as things are being done now or was it slightly different?
So actually, fusion energy research was classified and in the United States it was called Project Matterhorn, as far as I understand.
However, as we can see nowadays,
the problem of controlled thermonuclear fusion reactions to generate electricity is a lot harder than that of fission.
And so the scientists realise that like even the collective power of the United States,
the Soviet Union individually isn't going to be able to solve this problem quickly.
So there's a very famous fusion conference or the Geneva conference where physicists from the Soviet Union in the United States,
the U.K. and a few other places got together and actually compared what kind of theory they were using,
what kind of devices they were using, and are some really interesting things.
Like what was I think really interesting was not the differences, but actually the similarities between the approaches they were taking.
And that was really quite promising. And to some extent and it showed that actually everyone was thinking the same way about things.
And yet so to this day, fusion research, at least for energy purposes, for peaceful energy purposes,
has always been an area in which international collaboration has thrived,
particularly between allies during the Cold War, between the Russians and the Americans.
What is this related to the fact that unlike nuclear fission, nuclear fusion by itself does not lead to a nuclear bomb?
Yeah, that's that's a great point. So actually, every single nuclear weapon that exists today has at least a fission core,
which means that you need to have you need to understand fission before you can make a nuclear weapon.
On the other hand, if you just had a fusion plant,
you can't make a pure fusion weapon because you would need to understand the fissile material as well before that to make the weapon.
OK, so it's about time to bite the bullet as a human species, we've been trying to do this for 60 years, in which time we've got to the moon.
We've invented nuclear fission reactors, we invented the Internet bubble,
and we still don't have a nuclear fusion plant that produces electricity for Larin.
What are the challenges that mean that this has been a very hard problem?
Well, as we've discussed, it's not like a fusion can happen.
You need really high temperatures in the core of the device where the nuclear fusing as well.
However, at the edge of your reactor, the part which faces the wall,
you don't want it to be particularly hot because it's going to melt the material and you have something like hundreds of million,
100 million degrees in the middle. And material that we know today, as far as I understand, a few thousand degrees is pretty much limited.
So you have massive temperature differences between the two.
And the question is, how do you maintain this? How do you make the middle hotter and the outside just as cool as before?
And there are various physics and technology problems to it.
So, of course, on the technology side, you want material which does melt and all the physics side.
You want to understand that we hit it out from the inside,
out from the inside of what is that is the first time I heard the word in the podcast, but it can be a very important word.
So we should just so a Tokamak is so to talk about is one of the leading contenders for fusion power today.
And the way it works is that you have a doughnut,
basically something that's shaped like a doughnut and you put magnetic coils on the outside of what these magnetic coils do.
Stay the hold the plasma and confided, as we say in place to this, prevents plasma from touching the wall, mostly speaking.
And so essentially keeping it suspended from everything else.
And then you try to heat it up because the plasma is charged.
It will be contained by the magnetic field and because it has particles that it turns out follow the fuel lines.
So if you engineer your lines in a certain way, the particles will not go from one field to another.
What it does happen, but it's low compared to moving along the fuel line.
So you try to keep this very few lines and keep the particles from moving outwards.
And in fact, using magnetic fields to confine energy is this is basically an installation of insulating your muscles.
He doesn't move out. Installation, if I remember correctly, is about 10000 times better than the tiles on the space ship,
which prevents the crew from flying during re-entry, of course, in space.
And I think feels like that is going to come up.
OK, so just going to just there are these great challenges of containing the material and getting it to a high enough temperature,
but that does one more thing that's required to get fusion to happen.
I remember you telling me about these three things that were important. Yeah.
So to get, you know, a viable fusion power plant to get your fuel such that it can produce a lot of fusion power, you need three things.
You need enough particles. Right, because you want to combine the particles to fuse.
You need them to be hot enough. So you need to see really high temperatures because otherwise they're just bounce off of each other without sticking.
And then you need confinement. So you need density, temperature and confinement.
So again, enough particles that are hot enough and you need to keep them in the same place for long enough.
And if you can do these three things sufficiently well, then no matter what scheme you use,
you're going to you're going to be good at your produce fusion power from this.
And there's a way of measuring progress of the scientific community on all of these three goals.
Yeah. So this is the multiplication of density times, temperature three times confinement is referred to in infusion as the triple product.
And this is kind of the fundamental metric for performance of our devices.
And so if you look at where we were in the 1950s when research was first starting,
and then look at how the triple product of our devices changed with time,
you'll see that between the 50s and the 90s, they said, I guess fusion was progressing extremely rapidly.
It actually outperformed the famous Moore's Law.
So basically, the the triple problem was increasing faster than computer performance is increasing, which is really impressive.
There is, as you mentioned, up until the 90s, there has been a slight slowdown in progress, at least in terms of the triple products measure.
Yes and no. So actually,
an interesting point is that we've only ever actually run the kind of fuel that we expect will power the first generation fusion reactors,
which is deuterium and tritium. These are two isotopes of hydrogen.
We've only run this in two separate documents, one to talk about called FDR in Princeton and one at the talk,
Michael Jet in the U.K., actually six miles down the road from here.
So we've only actually had a few chances to properly verify this.
All the rest of the Tokamak used to term to Treasury usually now, actually, even though you don't get fusion power out of that or very much,
you can kind of say, OK, by making a determinate here and running this Tokamak.
But what would it look like if it were to him? Tritium, because the triple product, as you said,
to term tritium and we have got some talkbacks that have actually improved quite substantially in the past 10 years,
although it is true that progress has slowed.
And that's because basically we're all working on ITER, which we'll talk about later, I'm sure, which is the world's largest Tokamak.
And when that comes online, I think the progress will continue in the triple product quite substantially.
Yeah, kind of jump in. So progress seems to have kind of stalled in the 1990s,
but it's kind of because the entire community is is contributing to this one large experiment, ITER.
And so, you know, this this experiment takes a long time to build.
So we're hopeful that. If we wait, then we'll get a payoff and we'll see a very big improvement in either, but this is an experiment.
So please forgive me if this is not a good analogy, but would you say that for the nuclear fusion community,
the building of ITER is analogous to what the building of, say, the LHC was to be part of this museum?
Yes. Yeah, yeah. Well, let's talk about it now.
So it is a very, very large Tokamak nuclear fusion device that is currently being built in the south of France.
Yes. And it has to be so big because there are certain issues, things related to all of your research so that it wants to come in for Larry.
Tell me why it has to be so big or why it's been so big of this.
I think to me at least, the simplest way to understand this is about surface area to volume ratio.
So if you have lots of surface area and the same volume, you're going to lose heat very quickly.
But if you increase the volume, then you have less surface area per unit volume and then you lose heat more slowly.
And this is just the idea behind this is the simplest idea behind it.
You make it bigger than the surface area per unit. Volume is smaller.
You lose heat less quickly. And again, because it is bigger, the middle is for the filler in the meeting really takes longer time for the energy from
the middle to escape and not having a particle in the middle to escape to keep them down.
And so you have this actually happening. Yeah. So it's improving this confinement issue.
But you were saying one of these three main important issues.
So maybe we should briefly talk about what the big challenges for fusion and of where we are right now.
Sure. So we've talked about, you know, we need these insane temperatures to get fusion to happen.
And so it's kind of incredible that this is actually already been achieved.
So in a number of devices around the world, we can routinely create the conditions necessary for fusion.
The problem, however, is in order to heat the fuel to attain these crazy temperatures, we have to use a lot of power.
And so right now, the devices we have to put in a whole lot more power in order to keep the plasma hot than we actually get out in fusion power.
And so this is a problem because, you know,
you can't generate electricity if you have to put in 100 megawatts of heating to get one megawatt a fusion power out.
Right.
And so what ITER is designed to explore is, you know, if if we can create a device that can more efficiently achieve the temperatures that we need.
So if we can get a lot of fusion power out without having to put in as much energy in.
One of the remarkable things about fusion reactions, as I understand it,
from from reading your notes and talking to you earlier, is that it has potential to be self-sustaining further.
And could you explain to us what that means? Self-sustaining means you don't have to put in additional energy.
A candidate running, for example, if you put you know, if you want to have a barbecue, you initially have to heat it up with some of the lighter,
some starters to get the charcoal to a high enough temperature and a charcoal and a high enough to it starts to burn.
Right. And that creates the means. It breaks down and then it breaks down, creates more energy.
And this energy then breaks down further. And you'll have to put InterOil anything more light on it.
And it burns for the rest of your dinner, hopefully. So that's why we seek to achieve fusion that you put in enough energy to start
and then you have a bit of energy left running the Magna's and what you create
enough to flatten everything and just take in more power from the grid that
is self-sustaining in the way there are different regimes are poking about.
You're right. S self-sustaining reaction. It's not a power plant to be self-sustaining and you have to generate more energy into the grid.
So therefore you have to be more self-sustaining.
But self-sustaining fusion reactor is a master and we look at so what are the milestones, what we have here?
So first you have a reaction.
For example, let's consider, you know, the usual deuterium tritium into two different types of hydrogen coming together to give you energy.
OK, so to get them to stick together, you need to put in energy in the form of heating your coils,
the first level of the first milestone's break even, which means you need to produce more energy from the reactions to the amount of energy.
And this is doable in the foreseeable future without much improvement.
We believe, however, not all of this energy created goes back into the plasma.
Some of this is where you have the deuterium, tritium fusion. Most of the energy is releasing the neutron, which leaves the plasma.
So the energy which remains the plasma to continue heating it up is less.
So the next milestone is that you need to be able to generate enough energy, which means the plasma to continue heating it up so it doesn't cool down.
However, you also need energy to run the coils, to run the other things in the power plant.
And this is the next level that you want to be able to have it to generate enough energy, sustainable economic energy from the grid.
And after that, you don't want to create enough energy that you are making your power plants rather than a
scientific experiment so that you can you can generate energy to use for other applications.
And ultimately, we want this energy to be cheap enough to compete to compete with the other sources of energy on the market.
Otherwise, what people won't take it up? So there are these different states.
So the first stage, which we're not quite yet, but you think that we will soon,
is to have more energy released in the reaction when you put then the second stage is to have
more energy remaining in the plasma than you put in because some of the energy is very strong.
And then you have the third stage of having enough energy to run all the calls and all the plants staying in the plasma.
The fourth stage even of that being having surplus energy to then send to the grid and use actually the power plant,
then you have a four and a half stage off stage in time versus being economically viable.
And I should just say that it is probably going to get to the fourth the fourth stage.
Really? Yes, third or fourth at first.
That's how I mean it as an experiment. But that's the goal. OK, you all in various respects, research turbulence in these machines.
Jason, can you tell us a bit about how turbulence comes up in nuclear fusion and why it's
currently a problem for getting these reactions to work as well as we'd like?
Absolutely. It's so turbulent.
So, yeah, turbulence is one of the biggest problems in fusion, and it's actually the reason why we've made our fusion reactors so big.
The problem is, is that turbulence takes a particle that is in the cold fusion and it transports it out rapidly to the edge where it won't fusion.
And this decreases our confinement time, which is Justin says that's one of the components of this triple product.
So you you'd imagine if you know, if you put stuff in the core and it's transported out quickly, you'll get less fusion power.
So specifically in fusion reactors, one of the main drives, if not the main drive for turbulence, is something called the ion temperature gradient.
So basically all that means is when I go from an eye on temperature.
So I remembers the nuclei in my plasma.
If I go from basically room temperature or a couple of thousand degrees to hundreds of million degrees in the core,
and that happens over maybe like one or two metres, I think it is supposed to have a kind of radius of about two metres if that happens.
And two metres, then basically what that. Causes is that causes a lot of eddys, a lot of tonalities to form,
and basically this has been one of the key challenges of fusion over the past 30 years or so.
And people have tried to understand, OK, we have this turbulence, how can we suppress it?
And actually how can we use it to improve the confinement performance of our reactor?
So in a way, this is like if you're in a shop, in a shop, in the middle of winter, it's cold outside, it's hot on the inside.
You have turbulent eddies bringing the hot air from inside the shop into the cold outside in the cold outside.
So these are turbulent eddies.
And the way one of the ways you solve this is not put it all, but also if you put one at all, you have this hot, hot enough air just at the entrance.
And this could not have breaks these turbulent eddies such that you stop having a big ideological from inside the outside,
having a small area inside a small area on the outside. And this is showing a way this and this is one of the ways we try to reduce turbulence.
Go come up. Jason, you were telling us two things that you were saying,
that turbulence is a problem because it can bring this hot water from the centre out to the outside and you lose power.
But then you also mentioned that it could possibly be used to kind of make it more
efficient and think maybe that's related to something that just didn't work. Yeah, so I work I work studying turbulence and tokamak.
And in particular, I'm looking at ways that you can use all of this turbulent activity,
use all this energy and turbulence to actually fight the turbulence itself.
So we've heard that one one way to fight turbulence is to use to use this flow of air in the example of the shop on a good day.
And so similarly, if you use a flow of plasma, then you can shear turbulent eddies and reduce them.
And so I'm looking at a way that you can use the turbulence to create this flow of plasma in order to self-regulating the turbulence.
So you have turbulent eddies that are growing and getting more powerful and they create this plasma flow,
which then acts on the turbulence to stop it from growing.
And the methods that all of you use to study the flow in these plasmids,
how closely might that be related to methods that mathematicians back in the 19th century were using to study ordinary flows of fluids of water?
So depending on what kind of plasma physics you're looking at, you may use an extended version of the Navia Stokes equations,
which basically means you just add an external electro magnetic forces that come from the plasma, just just mathematical.
So the text equations are the classical analytical equations that govern the flow of Newtonian liquids.
So you're saying that some physicists use that, but with a tweak?
Exactly, yeah. And this type of a kind of fluid approach can actually be very fruitful when you're trying to look
at fusion plant design and trying to understand what kind of limits you can have in some cases.
So it is very useful. But there's another approach, which is, I think probably a lot more popular nowadays, which is called the kinetic approach.
So basically in that approach,
we have some kind of mathematical function called a distribution function that looks at the number of particles per unit area per unit velocity area.
And you can manipulate this in all kinds of interesting ways and you can actually derive fluid mechanics from it as well, which is nice.
So that's that's reassuring. But there are also lots of additional subtle effects, like when you add magnetic fields,
how particles orbit around it, for example, that fluid mechanics cannot predict.
I think probably the biggest one of the biggest examples of this is something called Landow dumping,
which is how electromagnetic waves can transfer energy to charge particles and using fluid mechanics like the Navia Stokes equations,
for example, you cannot predict this. You need to go to something called kinetic theory to predict this.
And kinetic theory forms the backbone of lots of the super computer simulations.
We do a lot of the theory we do nowadays because it's a very computationally intensive theory.
Exactly. You can't just run it on like your just desktop computer.
And yeah, it requires, depending on what you're doing,
maybe hundreds or thousands of computing calls to to be able to compute the solutions to your equations.
We've talked a lot about this huge international academic collaborations like with Peter,
all the private sector getting involved for the energy companies who are trying to make nuclear fusion devices.
Yeah. So there's there's a number of private fusion enterprises that have come up in the last maybe 15,
15 or so years with with varying degrees of repeatability.
And some of them really seem, you know, very out of this world, not really connected to reality.
But there are a good number of increasingly scientifically rigorous ones.
So some of the companies have started publishing in peer reviewed journals, which is encouraging.
Most of them choose a scheme that's different than the mainstream scientific community
simply because they don't typically have the resources to compete with devices like ITER,
for instance. And, you know, a lot of these a lot of these configurations,
a lot of these ideas are speculative, but that doesn't mean that they're not worth exploring.
So the private fusion industry has an interesting relationship with the mainstream scientific community, the mainstream academic community,
and that they're generally trying more fringe ideas that the mainstream community has kind of cast off.
But it's really in a lot of cases, it's very difficult to prove that these ideas won't work.
And there still is merit to exploring that. Right.
The main thing that annoys academic researchers about some of these private enterprises is they make they tend to make very grandiose claims.
So the academic community has been working on this for 50 years.
And then some new start up company says they're going to solve the problem in five and don't really give scientific data.
Supporting this claim rubs people the wrong way. Well, I can imagine.
So we're coming to the end of our time here, but it's time to put our chips on the table as it.
So, you know, it is measured away as we can possibly be.
Do you feel that at this stage, any sensible timeline can be put on when a viable, self-sustaining nuclear fusion reactor will be built?
Or do you feel there are still so many difficulties that need to be overcome that that's just not not a good question to ask.
Yeah, I'm telling me to take that.
Yeah. Yeah. So I would say actually getting to a commercially viable fusion reactor,
there is some time dependency in there, but I would actually say a lot of it is funding dependent.
So it's not a timing dependent question. It's a funding dependent question.
Obviously there are some constraints. We can do it tomorrow if we were given 100 trillion dollars.
But I do think that given historic funding levels for fusion have not really lived up to what a lot of people expected and hoped in the field.
I think we've made remarkable progress. I would also add that at current funding levels, kind of 20 50 is, I think,
a fairly reasonable timeline for when people are saying the first economically competitive fusion reactor will come on board.
I think if funding were increased substantially, I think we could probably do it, you know, quite a bit faster.
But I'm not quite I'm not sure if that's going to happen. Well, thank you very much for joining me.
It feels a privilege to feel at the cutting edge of fiscal endeavour.
I hope you've enjoyed listening. And please join us next time on In Our Spare Time.