The world's worst reactor idea: The OhioVR mantis reactor

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ohiovr
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The world's worst reactor idea: The OhioVR mantis reactor

Post by ohiovr »

Yet another fusion idea that will never work but it’s fun to think about..

We all know about sonofusion here as an idea that has been thoroughly discredited and all findings have gone totally no where and are unreproducible. But that doesn’t stop mad men (and lets face it, wanting to play with 200 million degrees is the definition of insane). After all, people have proposed all kinds of mad ideas that got quite far with funding and materials. I’m not suggesting this is something worthy of investment (personally I’m not sure any of them are) after all I’d not put my own money behind it if I had money in the first place. If I did have money I’d put my money into something sensible like dogecoin. And I’m not quite unscrupulous enough to con people into it. Like steam pistons banging on metallic plasma whirlpools. Or shooting plasma vortexes at each other. Or Using stadium sized lasers to fry a tiny capsule filled with fuel about the size of a grain of sand made of scientifically crafted radioactive by products of fission. Or giant battery banks that fry tiny wire cages (I have a soft spot for that idea). Or immensely complex and expensive power plant ideas based on worlds apart thermal regimes (My “contribution” to that went here: http://talk-polywell.org/bb/viewtopic.php?f=3&t=6459). Even if the idea did work or help or whatever, tokamaks are going to be huge, expensive, and mindbogglingly complex. Sure maybe its now only 5 years away. But in 5 years, is anyone going to want to pay 5 dollars per kilowatt hour? Or the polywell idea which is the name sake of the forum… People say Lockheed’s contribution was a failure but it was a great success at separating taxpayers from their unneeded cash.

Anyway back to sonofusion. Wait. Lets back up. Its cavitation that is doing the heavy lifting here, not glass beakers and piezo electric ceramics. A hardly compressible liquid wave culminates at around the center of a container which crashes into itself. As the wave bounces off itself it creates a tiny cavitation void filled with vapor and a very small, very brief bit of bluish light is released.

The ingredients here aren’t right at all for fusion. The time scale is about 1 pico second, the temperature is not even in the kilo EV range. The lawson criteron laughs at you, sonofusion.

But what the heck, cavitation is a pretty vicious force and that is the kind of thing that is still interesting for fusion. Recently scientists have observed an animal using cavitation as a weapon as in the case of the Mantis shrimp. If you’ve not heard of this genius little animal check it out:

https://www.youtube.com/watch?v=F5FEj9U-CJM

This little shrimp can produce far larger cavitation bubbles than beakers with ceramic actuators that yes, even produce flashes of light.

Classic laser fusion schemes, z-machine, the classic American H-Bomb design, and others work on focusing large amounts of energy to create high pressures and temperatures. So far out of all of these designs, only one was ever a success, the H-Bomb which uses xrays from a much smaller atomic bomb to compress and heat thermonuclear fuel.

Of course you know all that, you are the experts. I’d like you to put my idea to rest like all the others I’ve had. Perhaps the remnant of this discussion will dissuade others from considering it more in depth.

So the idea is pretty simple. Sonofusion will never work, the energies are just not there. It needs to be at least 10,000 times hotter, and the bubble needs to be active at least 10,000 times longer. How on earth can some arrangement of piezo transducers come up temperatures to vastly exceed the sun’s core? It can’t…

Enough foreplay I guess. So imagine a thick sintered and machined tungsten barrel about 2 meters tall. Perhaps the walls are 30 cm thick. The bottom is a mirror smooth parabola made of the same material with a focal point above it somewhere far enough away for the requirements of this design. At the focal point is a strong expendable hollow sphere with an opening facing the parabolic mirror, like again, tungsten, or perhaps tungsten carbide. At the top of the tube is a huge and thick free moving piston with insanely good tolerances (this is fusion, insanity is a must). The main cylinder is filled with some likely thermonuclear fuel. Maybe it’s deuterated acetone or heavy water. Maybe it’s degassed, or maybe it isn’t. Maybe it’s purposely got deuterium dissolved in it..

Here comes the jr high level contribution: High explosive shape charges are detonated on top of the piston shoving it down upon the “uncompressable” liquid with extreme violence, kind of like the orion spaceship in reverse. The action of this force sends a hypersonic shock wave down the column. Already the wave is in a state of cavitation. The energy could be anything you want. If you want to reuse this incredibly expensive piece of hardware we might have to tone it down a little. But for the sake of extremes this cavitating wave strikes the parabola and it travels to the center of the expendable hollow heavy ball. At the center of the sphere is the highest energies. The hope is that the energy is sufficient to fusion some of the fuel in the liquid. This concentrated wave travels into the sphere and bounces around for a while until it gets totally shredded. But the mass of the sphere should be enough to keep it in place long enough for the action of this super cavitation wave together for at least a few internal bounces. If enough reflections can happen before the sphere is destroyed it might satisfy the time aspect of Lawson’s criterion. The energies might just not anywhere near enough to fuse anything. But high explosives are quite a bit more powerful than little shrimp and piezo crystals. If the parabola had a gain of 40 db we might expect the focal point to be 10,000 times “hotter” than the planar wave coming into the parabolic mirror, already approaching at hypersonic speeds.

Likely outcome: a lot of expensive shrapnel and very pissed off investors. The parabola mirror is going to be pitted in the first shot so badly you could use it as a grind stone. It could never be practical for obvious reasons (it would take hours or days to reset and repair between shots). This didn’t bother Princeton and Sandia.. I suppose even if it did produce fusion it would be relegated to boring stuff like stockpile management of civilization destroying weapons.

That’s it I guess. I have no other ideas, “good” or bad. Feel free to shoot it down with High School level thinking. This is only 7th grade stuff.

At least the concept should be simple enough. If I had to give it a name I’d call it the mantis reactor.

I miss this forum. Glad to see others still playing around with ideas.



Premises:

1. High explosive pumped non fission thermonuclear nuclear device.

2. High gain parabolic reflector

3. Inertial confinement inside an expendable receiver sphere.

Immediate problems:

1. Irrecoverable pitting of the mirror

2. Experiment must be far from civilization

3. Device costs tens of millions of dollars. Probably requires the most ridiculous sintering kiln imaginable.

Proposed solutions:

1. expendable mirror
2. military jurisdiction.
3. Deep pockets with more dollars than sense.

Possible benefits:

1. Potentially lower cost stockpile management research.

2. And that’s probably it.

3. It’s fun to blow stuff up.

I hope this post makes more laughs than frowns. This is my only contribution here. At least I’m not proposing using atomic bombs as a propulsion system like significant minds did. If anything I've made everyone stupider for having made people read it down to this point.

Ivy Matt
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Joined: Sat May 01, 2010 6:43 am

Re: The world's worst reactor idea: The OhioVR mantis reactor

Post by Ivy Matt »

Sometime, when I find the time, I'll have to flesh out the elephant & deuterium balloon concept. I believe it was ChrisMB's concept initially, but since he didn't bother to do the math and engineering, it's up to someone else to pick up where he left off. Right now I'm weighing the costs and benefits of elephant shielding vs. using disposable elephants.
Temperature, density, confinement time: pick any two.

ohiovr
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Re: The world's worst reactor idea: The OhioVR mantis reactor

Post by ohiovr »

Ivy Matt wrote:
Wed Mar 17, 2021 8:08 am
Sometime, when I find the time, I'll have to flesh out the elephant & deuterium balloon concept. I believe it was ChrisMB's concept initially, but since he didn't bother to do the math and engineering, it's up to someone else to pick up where he left off. Right now I'm weighing the costs and benefits of elephant shielding vs. using disposable elephants.
I'd like to know more about this. I searched for elephant and there were 9 pages of results(!) Could you help me find what you are referring to?

ohiovr
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Re: The world's worst reactor idea: The OhioVR mantis reactor

Post by ohiovr »

Zap balloons of deuterium gas? Tell me more...

Ivy Matt
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Joined: Sat May 01, 2010 6:43 am

Re: The world's worst reactor idea: The OhioVR mantis reactor

Post by Ivy Matt »

It was just a joke, obviously, a throwaway example of a fusion "concept" someone might dream up but never realistically implement. I found the post. The context was Chris's list of fusion technologies, and particularly what sort of concepts should be excluded from the list:
chrismb wrote:Well, I think someone should care to make a list (and it can't really include theoretical ideas, else we'd have elephants sitting on ballons of deuterium before long and people say 'ah, but why not!?').
But it appears a similar idea was proposed earlier by Enginerd here (in the same context):
Enginerd wrote:Perhaps a 'Delusional/Impossible/Stupid' category, for ideas such as 'ask three elephants to stand on some hydrogen' or 'have a prayer group concentrate really hard on some holy blessed Boron'. Might prove amusing if nothing else....
Temperature, density, confinement time: pick any two.

ohiovr
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Joined: Mon Mar 02, 2009 6:36 pm
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Re: The world's worst reactor idea: The OhioVR mantis reactor

Post by ohiovr »

Ivy Matt wrote:
Thu Mar 18, 2021 5:44 am
It was just a joke, obviously, a throwaway example of a fusion "concept" someone might dream up but never realistically implement. I found the post. The context was Chris's list of fusion technologies, and particularly what sort of concepts should be excluded from the list:
chrismb wrote:Well, I think someone should care to make a list (and it can't really include theoretical ideas, else we'd have elephants sitting on ballons of deuterium before long and people say 'ah, but why not!?').
But it appears a similar idea was proposed earlier by Enginerd here (in the same context):
Enginerd wrote:Perhaps a 'Delusional/Impossible/Stupid' category, for ideas such as 'ask three elephants to stand on some hydrogen' or 'have a prayer group concentrate really hard on some holy blessed Boron'. Might prove amusing if nothing else....
That's really where my ideas belong :mrgreen:

I hope I'm not spoiling the forum. But since it's so quiet.. Well offense is not going to happen if there is no one there to be offended :mrgreen:

Ivy Matt
Posts: 703
Joined: Sat May 01, 2010 6:43 am

Re: The world's worst reactor idea: The OhioVR mantis reactor

Post by Ivy Matt »

I think most of the serious people have left for greener pastures.
Temperature, density, confinement time: pick any two.

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