This Fusion Startup Is a Strong Newcomer
Image: T. Bräuer/MPI for Plasma Physics
You all know I’m excited about nuclear fusion, don’t you. Because of all the technology that’s currently under development, this is the most likely one to dramatically change the world in the near future. It’d be clean and basically unlimited energy, so we could all stop pretending we’ll go vegan. This is why I’m having a close eye what’s going on and today I want to tell you about a very interesting new fusion startup in Germany.
In the past decade, nuclear fusion startups have sprung up in many countries, but the vast majority of them in the United States which now counts more than 20. Europe is as usual far behind and I was worried that Germany would miss the boat on that one entirely.
So I am happy about this new German startup. They called themselves Proxima Fusion and the news is that they just received $20 million in funding to get on the way. Their approach is a spin-off from the Wendelstein 7-x experiment in Greifswald Germany.
And since I know you’re really just here because of my German accent, let’s do this again. Wendelstein. Greifswald.
Wendelstein 7-x is what’s called a stellarator, and the new startup wants to use a more sophisticated version of that, a quasi-isodynamic Stellarator. That sounds super complicated, and it is, but the idea isn’t so difficult to understand.
The tried and trodden approach to nuclear fusion is using a tokamak, that’s a hollow ring basically with strong magnetic fields. It’s what the Joint European Torus used and what ITER is supposed to use, by the time it’ll finish construction, approximately in the year 4500.
But in he in those tokamaks the plasma tends to go unstable rather quickly which is a huge problem. Not only do you not get the nuclear fusion, you can actually damage your machine.
There’s a smarter way to do this by using a somewhat more complicated shape with elaborate magnetic fields. This configuration is known as the stellarator and the theory of it was developed already in the 1950s. The trouble is that back then they just couldn’t solve the equations.
It was only in the 1980s that that computing power had increased sufficiently to calculate what the magnets need to look like.
So you see the entire idea only became possible because of advances in an entirely different research area. And, as we will see in a moment, this is still the case.
At the moment, Wendelstein 7-x is the world’s largest stellarator. It’s about 5 and a half meters in diameter and weights a whopping 750 million tons. Its task is to test whether the magnetic confinement in the stellarator works as desired. You see here how this weird shape is built up from two layers of magnets. To generate sufficiently strong fields, the magnets need to be superconducting, so you have to cool them to a few degrees above absolute zero. Then you inject the fuel, and it follows this strange shape.
Wendelstein was not built to generate energy from fusion, but just to show that they could keep the plasma stable. In contrast to a tokamak, a stellarator should be able to run continuously and that in and of itself is bound to improve efficiency. So far they have managed to keep the plasma stable for 8 minutes, which is really amazing. Their goal is 30 minutes.
And they learned a lot of interesting things from this. For example, you might think that the nuclei in the fuel go around and around in the ring. And some of them do. But they can become trapped in part of the ring and then they go back and forth. And their trajectories are usually small spirals.
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