Comment on Actually it's pretty cool
barsoap@lemm.ee 3 days ago
Ions don’t move along field lines they want to spiral around them that’s why. The shape of the magnetic containment field is actually quite simple, take a donut, squish it a bit, cut it open, twist one end a couple of times and glue it up again. Five times in this case, seems to be a popular choice. It’s the coils generating that field where the geometry gets Lovecraftian.
This is the Proxima Fusion stuff, they’re planning on running the first surplus energy reactor early 30s and commercialise in that decade, the whole thing is designed for mass production with economics (build cost vs. maintenance vs. electricity price etc) in mind from the get-go. And yes they’ll pull it off it’s a spinoff of the Max Planck institute, not some garage tinkerers or VC fund techbros.
Yareckt@lemmynsfw.com 3 days ago
Interesting. Their proposed stelaris reactor only has four twists in it though if I interpret the Plasma’s shape as shown in their paper correctly.
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It could be due to the generators much larger size but that’s just a hobbyist’s guesswork. Here a comparison of the height of one coil to other reactors and a human:
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I’m not sure yet how much they are exaggerating with their capabilities and the reactors feasibility since I’m not a physicists and my only trust towards them stems from them working with the Max plank institute. But I hope it’s solid work. I’m looking forward to the reactions from other physicists to the plan though.
barsoap@lemm.ee 3 days ago
Yeah I’m blind that’s four. Having fewer twists means more coils have the same shape so it’s going to be cheaper to build but of course that’s just one dimension of a massive, massive, design space. That’s practically all they’ve been working on since Wendelstein turned on and exceeded everyone’s expectations by behaving exactly as predicted. Wouldn’t make sense to build a thing that gets Q > 1 but can’t compete with at least fossil fuels, in fact that’d be rather embarrassing.
Yareckt@lemmynsfw.com 3 days ago
Oh that’s a good explanation for four twists. It sounds pretty likely that this was factored into the design.
barsoap@lemm.ee 3 days ago
On second thought, assuming equal spacing and same size of torus, less twists actually gives less repeated coils than more twists. An uneven number sounds bad for repeatability, though, and six might either be too much (ions don’t want to twirl that fast) or the coils get too complicated to still be amenable to proper mass production or something.