Proxima Fusion builds a stellator. As far as I remember they were founded by wendelsteinians.

They are the only fusion startup I know of that was faster than their own timeline in the last year.

It'll be really funny if we get a commercial fusion device before ITER has even been turned on.

I'm sure they developed some really useful technology in the process of building the thing, but I suspect they would have made more progress faster if they had taken a more iterative approach.

Good list, I'm also keeping an eye on Tri Alpha Energy and First Light Fusion. TAE recently announced [1] initiating a field reversed configuration with no plasma injectors, only neutral beam injection, which is a pretty big deal in simplifying the design.

[1] https://tae.com/tae-technologies-delivers-fusion-breakthroug...

Thea Energy is working on a stellarator that doesn't require the complex shaping coils that W-7X is using. I'd put them above Helion and below CFS, but in a couple years they might take the top spot.

4. Acceleron (muon catalyzed)

There's huge advantages to muon catalyzed if they can get it to work. Plants would be orders of magnitude smaller and cheaper to build.

[0] https://www.acceleron.energy/

I doubt Helion will work. By their own paper using simplified model their device allows theoretically for Q no more than 2 (2 times energy produced versus energy spent). They claim with their like 90% efficient capture they still get net energy gain. But typically reality way messier than model and I will be surprised if they archive Q=1.

Tokamaks main problem is plasma instabilities. While Commonwealth may archive high Q briefly, nobody knows how plasma will behave at those conditions and long operations may not be possible.

Stellarators on the other hand do not have plasma stability problems. So my bet is on those.

what about general fusion?

https://en.wikipedia.org/wiki/General_Fusion

So on this graph they're at about 0.2e20, but it also says they need 3e21 (and the graph on Wikipedia agrees)... So are they 150x off the target? 3e12 is a typo I guess?

If we ever have access to unlimited cheap energy, then we are going to boil the world.

The goal posts on AGI would be superluminal and somewhere back in the 1400s if they were physical objects. I’ve never seen or heard of a field so deeply in denial about its progress.

For every major trouncing of criterion we somehow invent 4 or 5 new requirements for it to be “real” AGI. Now , it seems, AGI must display human level intelligence at superhuman speed (servicing thousands of conversations at once), be as knowledgeable as the most knowledgeable 0.1% of humans across every facet of human knowledge, be superhumanly accurate, perfectly honest, and not make anything up.

I remember when AGI meant being able to generalize knowledge over problems not specifically accounted for in the algorithm… the ability to exhibit the “generalization” of knowledge, in contrast to algorithmic knowledge or expert systems. It was often referred to as “mouse level” or sometimes “dog-level” intelligence. Now we expect something vastly more capable than any being that has ever existed or it’s not “AGI” lmfao. “ASI” will probably have to solve all of the world’s problems and bring us all to the promised land before it will merit that moniker lol.

> AGI by Turing’s definition is here

Is it? AI is impressive and all, but i don't think any of them have pased the Turing test, as defined by Turing (pop culture conceptions of the Turing test are usually much weaker than what the paper actually proposes), although i'd be happy to be proven wrong.

Putting a bunch of much more viscous radioactive material within proximity of each other is simpler than squishing and maintaining confinement of plasma under extreme conditions.

Fission reactors are relatively "easier" to simulate as giant finite element analysis Monte Carlo simulations with roughly voxels of space, i.e., thermal conductivity, heat capacity, etc. I happened to have been involved with one that was 50+ years old that worked just fine because of all of physicists and engineers who carefully crafted model data and code to reflect what would be likely to happen in reality when testing new, conventional reactor designs.

The problems with fusion are many orders-of-magnitude more involved and complex with wear, losses, and "fickleness" compared to fission.

Thus, experimental physics meeting engineering and manufacturing in new domains is expensive and hard work.

Maybe in 200 years there will be a open source, 3D-printable fusion reactor. :D

The difficulty is in the details. Small differences lead to bigger differences, like in chaos theory [0] What if the model says this coil needs to be 23.1212722 centimeter? Or two coils need to be 37.1441129 centimeters apart? How do you build that? Mathematics is always much more precise than engineering.

[0] https://en.wikipedia.org/wiki/Edward_Norton_Lorenz#Chaos_the...

We still have wind tunnels and aerodynamics is a pretty simple problem compared to fusion.

Same question got asked of Bob Bussard when he visited Google to talk about his whiffle-ball design. It's not that we lack models, it's that they're effectively incomputable at the scale we'd need them to be.

In a fluid, effects are local: a particle can only directly effect what it is in direct contact with.

In a plasma, every particle interacts with every other. One definition of a plasma is that the motion is dominated by electromagnetic effects rather than thermodynamic: by definition, if you have a plasma, the range of interactions isn't bounded by proximity.

This doesn't apply quite so much to (e.g.) laser ignition plasmas, partly because they're comparatively tiny, and partly because the timescales you're interested in are very short. So they do get simulated.

But bulk simulations the size of a practical reactor are simply impractical.

Give them the funding and they would love to start ..

But there is a german fusion startup about to build a stellarator.

https://www.proximafusion.com/about

(I assumed there was some sort of cooperation with Wendelstein, but found no mentioning of such on a quick look now)