So, the people here, with letters after their names, will quickly disabuse me of my glorious insight. I am ready for it.
I was looking at the potato chip design (stellarator?) when a thought occurred to me. Would it be possible to build an above-input fusion reactor based on collision?
I picture three intersecting (tetrahedral alignment) retention loops (like tokamak loops, but less squeezy). Each loop would establish a cyclotronic flow in the contained plasma, but not to collider-level speeds, merely fast. The loops would push the plasma into the center chamber, where ignition would take place because the plasma is getting shoved into the other plasma.
Since there will be charged particles exiting the collision chamber, the pick-up side of the loops could capture some direct power from the flow (slowing it back to flow speed, if’n that makes sense). The blanket would wrap the chamber and extend partway into the loops (because neutrons follow straight lines, so the outer part of the loops would not be exposed).
The chamber, of course, would have to have its own magnetic confinement regime, so that the plasmas would flow into each other and escape along the appropriate channels.
Perhaps instead of tetrahedral, it would make more sense to use four counter-rotating flows in a sort of toroidal alignment (in perpendicular planes), so that the collision would be nearly head-on. Or some other arrangement.
I followed your instructions as carefully as I could, and it seems to work okay. Can’t seem to reliably get more than a few terawatts out of it though.
Creating fusion is a lot simpler than this. I don’t know why folks come up with all of these designs. Here, I’ll give you the secret…think big. Just get a lot (and we are talking Hitchhikers Guide sizes here) of hydrogen…about 2/3rds of a solar mass ought to do it, perhaps a big less. Then…just let gravity take over. Simple! And I can guarantee you it will work. Don’t believe me? Just look up in the night sky to see proof that fusion is not 30 years out, but instead we’ve had it for over 13 billion and counting.
But, if you HAVE to make it complicated, I think you were thinking of the Stellarator. It does look a bit like a potato chip, come to think of it. Sadly, I’m neither an expert on fusion nor do I play one on the SDMB, and I haven’t stayed at a Holliday Inn Express in…well, years. However, here is a cool video from a futurist I follow who can at least tell you all the benefits if you get your design to work.
Actually, I mentioned the stellarator, right there in the tldr you quoted. The challenge the stellarator addresses is that the outside of the tokamak plasma ring moves slower than the inside, so they twisted the ring to have a sort of möbius effect, to balance the sides. The paths do not actually cross.
I do not entirely disagree with your over-arching point, though, that fusion is probably a fool’s errand.
Oh, I don’t think it’s a fools errand at all. The potential gain is incredible and worth the expenditure of effort to try and make it a reality. My ‘over-arching point’ was really just making a rather lame joke…some think fusion is impossible, but we know it can be done on cosmic scales…you just need a star.
Another way you could do it, if you watch the video I linked too, is build a really, really large and robust hole in the ground, fill it partially with water with a tunnel and turbine and drop a hydrogen bomb in…there you go, fusion power. I think that with some of the new materials likely to become available in the next decade or so that, eventually (maybe not in MY lifetime), viable fusion power that gives more energy than it takes to create the reaction, will happen. And it will be a game changer.
Technically, that is a bit shy of completely accurate. A thermonuclear device (H-bomb) is only partially fusion. It uses a fat-man-style fission detonator, a plutonium “spark-plug” within the fusion charge, and a U-238 hohlraum casing to enhance the explosive power of the bomb – the цар бомба test explosion only yielded 50 megatons, instead of the theorized 100, because the Russians used an inert (non-fissile) hohlraum.
Every H-bomb still uses an A-bomb to light up. Dropping an H-bomb into a pit of water involves quite a lot of fission along with the fusion, so the cheap, abundant fuel must be enhanced with the other stuff that is expensive and hard to find.
I think the engineering of getting the stuff to collide could be tricky.
In those big colliders like CERN uses, the collision is essentially one-dimensional - stuff is being flung around a tube, but really, it’s just axial to a very long electromagnetic accelerator, colliding with something else coming the other way made easier(a relative term, I’m sure) by the fact that the stuff coming the other way is also more or less axial to the apparatus.
If you’ve got a bunch of those things feeding into a reaction chamber from different directions, it seems like you’re adding extra orders of magnitude of difficulty - head-on collisions are just more likely to work than T-bone type collisions - also, if you’re feeding in from different directions, you have to be able to maintain containment and alignment in the last inch of travel, without upsetting the last inch of travel for all the other directions - I suspect it’s a big old challenge to design magnetic fields that work so finely, so close together, but with different agendas each.
But IANAPP, so that’s just a load of old waffle, I expect.
If I’d heard, “Example of a stellarator design, as used in the Wendelstein 7-X experiment,” in a Trek episode (any of them) my eyes would roll back in my head so far they’d hurt.
Valid points, yes, but what you are talking about is high-speed research collisions, where the beam itself is nm thick (a few protons across) traveling at near light speed. What I am talking about is plasma flows mm thick at the focal point at shockwave speeds (maybe a couple thousand m/s), where the goal is not precision targeting but just shoving a bunch of stuff together hard, to get a good burn.
The loop fields would be kind of independent, designed primarily for pumping the flow around the path; the chamber itself would have its own set of magnetic fields, aligned to channel the incoming flows into the focal point and thence out toward the drive loops. It might work, or, as you say, I might (probably) be making waffles.
Um, yeah, that’s one of the non-trivial engineering challenges here. If we had a chamber that could contain two high-speed jets of plasma running into each other and fusing (and all the random collision bounces and fusion products), we could use that to make a much simpler fusion device. Magnetic confinement is hard.
Wouldn’t it be more convincing to look up in the daytime sky?
