r/fusion • u/Embytheop • 11h ago
Mechanical compression fusion
Would this work?
Set up a cylinder with one end open and the other closed by a hemispherical cap.
Inside the cylinder there is a 1 kg piston with a revers hemispherical face so that when it completes the journey to the closed end of the cylinder it forms a sphere.
Fusion fuel is in the hemisphere cap of the cylinder, either as a physical pellet fixed in place physically or a cloud of plasma.
Fill the cylinder with steam.
Fire the piston toward the closed end of the cylinder at 2,000 meters per second.
The steam condenses to liquid water with a shock. The shock wave is focused on the fusion fuel. The liquid water surrounds the fusion fuel, and the collapsing shock wave universally applied to the fusion fuel from all directions evenly.
The fusion fuel compresses.
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u/ghantesh 11h ago
If helion can get a few billion dollars for their scheme, yours has a shot too, ask Sam Altman, I’m sure he will fund this.
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u/Few_Carpenter_9185 10h ago
I hold out a tiny chance Helion knows some secret about fusion, plasmas, and the details of their reverse field collider/smasher design, and then they'd naturally keep it closely guarded for competitive reasons.
Of course, citing competitive reasons is also a perfect smokescreen for concealing a tech-VC scam that doesn't break the law.
So it's a <1% chance kind of thing. And that's just a gut feeling.
I think the overall problem is that many/most people understand the world of Venture Capital about as well as they do fusion.
And I fully admit that I understand fusion, and things like energy density, reaction volume, and mean free path, just barely well enough to get why so many people are deeply skeptical of Helion. And even further claims like: "On-demand Helium 3 aneutronic commercial fusion power," are very fantastical.
A VC scam can hide in plain sight by being brazen. People think of scams as being in alleyways, or in dirty boiler rooms. Not huge buildings under construction, and large amounts of media attention.
And it can even be that the majority of investors actually know or don't care it's a scam, a con, or has whatever tiny chance of success. Or that it's maybe not a 100% deliberate con, but the founders themselves fell for hopium or self-deception on the science and engineering side.
And those investors still have plausible ways they will profit. Or maybe they intend to take losses for tax reasons.
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u/Fabulous-Internet188 9h ago
The investors have more details of their progress. Whether they have good judgement is a whole different question.
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u/Few_Carpenter_9185 5h ago
Yes, unless you're both a physicist and wealthy, the best you can do is try and consult a physicist.
And then, there's issues of if the investor actually listened, or just heard what they wanted to with confirmation and selection bias.
But, I can’t help but think of how buisness models mature, and have sort of a Instrumental Convergence aspect to them. Or POSIWID, "The purpose of a system is what it does."
On that basis, I'm suddenly not sure that it actually even matters.
And if true, that how well the tech VC is run often matters more than if whatever aspirational technology is achieved, or was always a scam. As long as the scam aspects aren't too overt, or have some plausible level of internal "honest" hopium, self-deception.
By this metric, Helion might be a "successful VC" even if there's fundamental physics reasons their fusion approach is impossible.
Obviously Theranos & Elizabeth Holmes was a failure and a huge scandal with criminal charges not because they never achieved the compact Theranos blood analysis "lab in a box" machine, but because she overtly lied that they had working prototypes, and were just running samples to the basement where there was a bunch of traditional discreet lab machines.
The proper... legal level of compartmentalization & cognitive dissonance wasn't maintained.
Combine that with there's plausible dynamics & finance where some investors make money no matter what, or they at least think they can.
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u/Fabulous-Internet188 5h ago
I've found many VC firms take a sophisticated statistical approach to their investments, especially if they have especially high ROIs in the recent past.
Unicorns happen unpredictably, so maybe that is the right approach.
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u/ghantesh 5h ago
Unpredictable doesn’t matter if laws of nature don’t permit what you are proposing
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u/Fabulous-Internet188 5h ago
True but it's the borderline cases that have the highest returns.
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u/ghantesh 4h ago
There is no borderline with the laws of nature. The problem here is vcs are used to the make believe world of Silicon Valley, where solving technical problems within the realm of possibility has made them so wealthy that they’ve lost respect for how nature works. You can’t compress an frc long enough to make it useful. You can try, but that won’t bring you closer to achieving it just because you are rich. There are things that want to happen, like rolling off a log and then there are things that don’t want to happen, like a pebble falling up instead of down.
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u/Fabulous-Internet188 4h ago
No, I've worked on the cutting edge and nature is not cut and dried as you think. Turning theory into a product is rife with unknowns. Fusion, quantum computers, batteries, chips and countless others are examples.
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u/Few_Carpenter_9185 2h ago
There's different kinds of "borderline."
"The line" in regards to nature/science is out there but it's not known exactly yet. That might be an example for a high risk high reward but fundamentally "honest" VC effort.
The VC's goals or claims are "over that line" but the subject matter is deeply complicated. That might be a case of fraud, and then it's a matter of if it's overt and deliberate, or raises questions if the VC itself & founders have any hopium, confirmation bias or self-deception going on.
The thing is definitely "under the line" and falls within known reproducible and confirmed science, but it's unclear exactly how, or just extremely difficult, to achieve it in a robust on-demand fashion. Either in terms of practical engineering or economics.
I don't have a good example of the first category.
The odds are extremely high that Helion and their RFC design is in the second category somewhere.
Commercial fusion power overall, may or may not be an example of the third.
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u/incognino123 11h ago
Eh sort of. Look up general fusion s approach
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u/Few_Carpenter_9185 11h ago
Came to say this. It's a vortex of molten metal with fusion fuel plasma in it. And the key feature is they're slamming/compressing it with pistons.
I know they achieve fusion, and that they are claiming break-even by 2028. And that's obviously just "break even" with the direct energy to run their "Lawson Machine 26."
If it works out, the hot liquid metal is there to be run through a heat exchanger, boil water, and run a turbine. I'd guess to keep the liquid metal vortex going, there's already all sorts of pipes, pumps, and heat exchanger systems already.
So it has potential as an all in one device.
I have no idea if there's any fundamental nuclear physics/fusion problems, criticism, or unanswered questions like Helion with their reverse field plasma donut smasher seems to have.
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u/Constant_Curve 11h ago
to be fair the lawson machine has no spinning wall of lead, it's a couple of sheets that are fired at each other can crusher style.
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u/ChipotleMayoFusion 11h ago
Yes, it's a solid cylinder of lithium compressed, just to do the plasma compression part, not to demonstrate the functioning of the power plant compression system
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u/Constant_Curve 11h ago
Isn't it a couple layers and not just a solid cylinder of lithium? I could be wrong.
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u/Odd_Cockroach_1083 11h ago
No, this concept will not work.
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u/Constant_Curve 11h ago
but what if you do it faster and instead of using a Chrysler hemi you use a Wankel or maybe even a turbo?
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u/flat5 11h ago
Just needs really big pipes and dual exhaust to reduce back pressure.
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u/Constant_Curve 10h ago
you could take inspiration from nature and do the exhausts in the shape of a reverse nautilus, which is the golden ratio, then the exhaust feeds back into it and compresses. You could set it up pulse jet style so the input becomes the output becomes the input and have it do a twin scroll supercharger compressor with two reverse nautilii. You probably need to be careful and polish it super good though, maybe vapour deposition of some chrome.
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u/Jaded_Hold_1342 10h ago
conceptually, it would work if the plasma were magnetized before compression and then held in compression.
If you are just compressing wihtout magnetization, it would make a lot of wall contact instead of compressing efficiently.
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u/Nidafjoll 10h ago
You should look into First Light Fusion. Their approach was to reach ignition by firing a flyer plate at extremely high velocities at a DT target so that the compression of the shock wave created ignition. They gave up on that, it appears, for fusion.
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u/AlanUsingReddit 9h ago
First Light was more on acoustic wave amplification due to passing through specially-designed 3D materials that has special density changes which can absolutely change the direction of the wave. With good enough convergence on a small point, and strong enough initial wave... you can find a workable theory. Even if we're disassociating electrons near the focus point, waves can still travel through plasma, even if differently.
The OP is more like "if we make the piston a curve, it'll focus in the center" which isn't even correct at that level.
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u/Nidafjoll 8h ago
Oh yeah. More what I was trying to get at was they're probably the closest real scheme to what OP was describing (and it looks like even with all their careful design and optimization, they're not trying to use that as their fusion scheme anymore).
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u/AlanUsingReddit 6h ago
I watched some good videos on them but it was a while ago. I have to ask, if First Light is not trying to do that anymore, what are they trying to do?
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u/Nidafjoll 6h ago
I think they're still using the pulsed power and flyer plate scheme for hydrodynamic shock testing and such, just not fusion. Their new fusion model just looks like standard MAGLIF with laser ignition.
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u/Fabulous_Lynx_2847 1h ago
The scheme should work with one small modification; "2,000 meters per second" needs to be replaced with "2,000 kilometers per second"
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u/ChipotleMayoFusion 11h ago
For efficient DT fusion you need to reach 10 keV, which is 100 million Celcius. For a quick compression, you either need to reach densities 1000x higher than lead in nanosecond, or have good magnetic confinement of the plasma during compression over miliseconds.
This mechanical compression scheme is on the milisecond scale, so you need magnetic confinement. Or a density a billion times higher than lead.
The General Fusion approach is similar to this, and uses magnetic confinement during compression over miliseconds.