TAE fusion machine’s breakthrough design, with Director of Diagnostics Thomas Roche

Good Clean Energy is a podcast that tackles one of the most existential questions of our time: how to build a world with abundant, affordable, carbon-free electricity. This season we’re going to unpack all the things that TAE is working on to make fusion energy a reality.

In this episode, TAE Director of Diagnostics Thomas Roche discusses his groundbreaking paper that showcases a significant advancement in fusion energy research. The conversation delves into an experiment that drastically simplified TAE’s fusion research machine, leading to a first in the field. Roche explains how neutral beam injection replaced complex formation sections, reducing costs and complexity while improving performance. These developments mark a significant step towards creating efficient and economical fusion power plants in the future.

Covered in this episode:

• Understanding TAE’s fusion approach
• Innovative experiments and surprising results
• Implications for TAE’s future fusion machines
• Reducing cost and complexity
  

Jim McNiel: You know, we are facing a lot of big challenges as a society. And I always ask the question, there’s so many levers to pull. What’s going to have the biggest impact? I think the answer is energy, clean, sustainable, environmentally friendly energy. You’re listening to Good Clean Energy. I’m your host, Jim McNiel.

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McNiel: The world has been chasing fusion since the 1940s, the atomic age of fusion. And some of us wonder, why is it taking so long to get to this point where we can harness the power of the atom for good? And most of us think it is taking too long. But many of us, most of them scientists, remind us that it’s a process that while fusion exists, it is the chosen form of energy in the universe —every star is a fusion reactor — it’s not easy to replicate on earth. It’s a process of experimentation and research and trial and error. Today we’re joined by Dr. Tommy Roche. He’s a Director of Diagnostics at TAE Technologies, and he’s lead author on a very exciting paper that we’re going to discuss today. I’d like to welcome Tommy Roche. 

Tommy Roche: Hi, Jim. Thanks for having me. 

McNiel: So let’s create a baseline for some of those who aren’t as familiar with TAE and what we do. Let’s start with our flagship machine. That’s our fifth-generation machine called Norman. And if you could explain to us how Norman creates plasma and sustains it. Let’s start with that. 

Roche: Norman is what is called a field-reversed configuration fusion reactor device. And what it does is it creates a ball of plasma that a current flows in that causes it to create these closed magnetic field structures. And these closed field lines make the imposed magnetic field reverse, that’s why it’s called a field-reversed configuration. And this current is sustained by the injection of neutral beams. 

So neutral beams are basically hydrogen atoms that are shot at a very high velocity. And since they’re neutral, they’re able to move past the magnetic field. When they interact with the plasma, they get ionized and their velocity carries in with them current.

 And this current keeps the magnetic field reversed and heats the plasma as well. So as the plasma gets hotter and hotter, we can increase the magnetic field and reach fusion-relevant temperatures. And the hydrogen atoms start to fuse with each other. 

The Norman device had what we call the formation sections. In technical terms, they’re a theta pinch coil. And we use actually 13 or 17 theta pinch coils on each side that push the plasma and accelerate it to a very high velocity of about 300 kilometers per second. And this generates two FRCs in a very fast process using pulse power and up to 100 gigawatts of energy that exists for about 10 microseconds. And these FRC smoke rings move towards each other in the center of our confinement vessel and collide and generate an FRC. 

So the point of the two rings colliding into each other, they come with a lot of kinetic energy. In other words, they’re moving very quickly and all that kinetic energy basically becomes thermal energy. When the two collide, they join into one larger FRC that has a very high temperature and a relatively high density. This density is now high enough for the neutral beams to be captured. and for the reactor to start heating up and go through that process I was talking about earlier.

McNiel: So the easiest way to understand this is that if you clap your hands together, they’re going to get hot. 

Roche: Basically, yes. 

McNiel: Yeah. Okay, so we’ve created these plasma rings or superheated gas in the formation sections and we crash them into the center. And it becomes a combined FRC and then we keep it spinning and it gets hotter. That’s basically what Norman does today. 

Roche: That is what Norman did as it was initially designed. What it does today is a little bit different. I wrote an experiment that I said, Okay, we would try to operate the machine without formation section and with a couple other things. All we needed was the neutral beams and the right set of  conditions of the initial seed plasma to get the field to reverse without using the theta pinch coils. 

McNiel: That must’ve been quite a shock to the team that that happened. 

Roche: Yeah, I remember having my jaw drop that day. I was kind of half-heartedly expecting the experiment to be interesting, but I never thought that it would lead us to the state that we’re in now.

McNiel: Wait, so to be clear we had these very complex sections of the machine called the formation sections, where we inject superheated gas, heat it up to a plasma, accelerate it towards the center of the machine and collide it in the middle, which is how the whole thing gets started. And you took all that away. 

Roche: That’s right, we just turned it all off for one day just to see what would happen. And it turned out that  we were already in the conditions that were necessary to generate field-reversed configurations just by neutral beam injection alone. 

This isn’t the first time people have tried to do this. There’s been quite a few attempts at injecting particle beams and generating reverse fields. There have been experiments that date back all the way to the Seventies where this was attempted. 

But at TAE, we’ve developed the beam technology that has allowed us to enter into the space where this is possible. And we’ve done it long enough now that we have a really good theoretical understanding of the process, and how it works, and why some of the earlier trials didn’t work. And having figured all that out means that we can move towards the next step of Copernicus and beyond. 

McNiel: So what was the peak performance achievement for Norman versus the same for Norm in terms of temperature and confinement time? 

Roche: So I believe that we’ve at least doubled all those parameters in the Norm regime over Norman. 

McNiel: So you basically took away half of the hardware and you got twice the performance?

Roche: Basically. Now it’s not necessarily just because we removed that part of the hardware, but we got better and better at running the machine along the way. So part of it was the simplification of the machine and being able to do things more compact so it minimized losses and impurities. But the other part was just becoming proficient at the operation of the machine over time. 

McNiel: So instead of spinning plates while riding a unicycle, you just took away the unicycle and you could focus on spinning the plates. 

Roche: Something like that. 

McNiel: Okay. Well, that’s kind of mind-blowing. So you ended up getting double the performance with nearly half of the gear, and now this is the new platform going forward for the design of Copernicus. 

Roche: Exactly. Copernicus will have more power and more beam injection, but now we know what the important things to focus on are, so we’re focusing on those and leaving out the rest.

McNiel: So can we sell those formation sections on eBay? Is that something we can do? 

Roche: If you can find a buyer, I’m sure. In fact, that was another component of the formation section that was nice to get rid of. The quartz tubes that were required to do this really fast generation of the FRCs with the theta pinch were prohibitively expensive and finding manufacturers for them was no easy task.

McNiel: And will this development shorten the timeline for building Copernicus? 

Roche: Absolutely. If I think back to when we were building Norman, there was a big crunch of a couple of months when we were working basically around the clock to get the formation sections ready for  the program to start. And now we can avoid doing all of that, and it was a very complex system that had to be built to do the formation section.

McNiel: Okay. So instead of forming rings and crashing them into each other, you’re creating a plasma in the central vessel and energizing it with neutral beams.

Roche: Yes. We’re energizing with neutral beams, but we’re also creating that current that causes the field to reverse and causes the confinement to improve both the fast ions and the thermal plasma.

McNiel: Okay, so to a layperson, it would make sense that if you’re not using the formation sections of the machine, you could just take those away.

Roche: Exactly, and that is what we’ve done. 

McNiel: That’s a good portion of hardware you no longer have to build or, or manage, right? 

Roche: That’s right. If you want to put it in terms of, say, an automobile, imagine your starter motor costs ten times as much as your car, and you had to lug it around everywhere you went. But if you found a way that you could just start the car by igniting a piston rather than having the whole starter motor to get things going. I would liken it to that. 

McNiel: So we’re removing a whole bunch of hardware here. So in terms of the total impact in terms of cost of goods, I mean, what are we saving by taking all the formation ends off and the things that power it and the diagnostics and so forth? What does that mean in cost of goods? 

Roche: That’s probably about 25 percent of the cost of an experimental vessel. 

McNiel: We’re not talking about a full power plant. We’re talking about the next level generation machine. Okay, well that’s quite significant. We’re reducing hardware costs. Does it reduce complexity and diagnostics issues and things of that nature? 

Roche: It’s a significant reduction in complexity because like I said before, the formation sections — the theta pinch coils — require pulse power. And that means you need a huge amount of energy storage and quick delivery of it. And those kinds of parts are complicated, takes a lot of engineering to get them to work and they degrade over time because they have to produce these huge currents and deliver a lot of power. And the other problem with it is it’s very inefficient. 

McNiel: What do you think is the best takeaway for this paper that we should know?  What makes you excited about it? 

Roche: I’m excited that we’re now able to do what people have tried to do for decades and do it efficiently with a clear understanding of the process and how it will bring us to a very efficient and very economical fusion reactor at some point in the future. 

McNiel: Tommy, we’re really excited to read your paper for those of us who can understand it. And we’ll drop a link into the show notes here and thank you so much for the hard work into producing it. 

Roche: Thank you for having me, Jim.

McNiel:  Thank you for listening to Good Clean Energy. This season we’re going to unpack all the things that are going to make fusion a reality. The energy source that’s going to power the planet for the next hundred thousand years. I’m pretty excited. I hope you are too. Thanks for listening. This is Jim McNiel.