Conditions required for fusion to occur

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
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Frank Sanns
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Conditions required for fusion to occur

Post by Frank Sanns »

There seems to be many ideas out there and on this forum of how to do fusion. It is important to remember that fusion does not just "occur" when SOME parameters are met. This is true with magnetic fields, poly wells, high voltages, confinement, etc..

It is not just good enough to form a gathering of fusible atoms or nuclei in a container or in space. Not even a whole bunch of them in a small area.

Using electrical, magnetic, high pressure, gravitational, or anything else alone, will not create any significant amount of fusion. This is true even if you could strip every single electron from deuterium or other fusible materials. No pile of nuclei will ever fuse, at any appreciable rate, even with every single electron gone. I say at any appreciable rate because quantum mechanics is never zero but for my examples it might very well be for any practical purposes.

The pile of nuclei still have a net positive charge that will repel other nuclei. This force is vastly stronger than any macroscopic force that we see in everyday life. Until a Herculean amount of force is applied to bring two nuclei together, fusion does not happen.

The force is the key element in fusion. High voltage alone does not cause fusion. You can have all of these nuclei traveling together at 100 KeV and no fusion occurs. It is only when a sufficiently powerful atomic force is applied two overcome the coulomb repulsion between nuclei that there is any chance for fusion. There is no source of such direct force on earth to do so.

To achieve fusion, the force can only be attained by collisional deceleration of high speed nuclei. It is the stopping of colliding nuclei over a very short distance that supplies the force needed to overcome the coulomb barrier or more precisely the energy barrier for tunneling.

So for fusion, high rates of dV/dt is the only way any of the existing fusion approaches work. Force is proportional to change in acceleration (F=ma). How that is achieved uses multiple elements to get the nuclei into a high velocity state so when they encounter another fusible nucleus, they can start to participate in the statistical quantum tunneling game.

Anything short of supplying these huge collisional forces will not result in fusion no matter how much confinement there is.
Achiever's madness; when enough is still not enough. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
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Richard Hull
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Re: Conditions required for fusion to occur

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The key point is that you must impart phenomenal collisional kinetic energy to the fusion fuel nuclei to even begin the fusion process! Once you have this condition met, you are only allowed into the casino. It is only now that you are able to merely roll the dice at the Quantum level fusion crap table and see if you can win against the quantum odds. BOHICA! Bend Over, Here It Comes Again.

It is like Don Lancaster use to say... "You are forced to play the game....The game is rigged and it's the only game in town."

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: Conditions required for fusion to occur

Post by Dennis P Brown »

You hit the nail on the head; I like to point out that our Sun, with its staggering mass and huge core temp still only produces about 500 watts per cubic meter - and that cubic meter is many millions of degree C and about 10^28 atoms/m^3. A fusor is lucky to have 10^20 atoms and if I calculated correctly, about 10^5 C "equivalent temperature" on average; a lot less than the Sun in all respects. As for energy, well, that has been discussed endlessly here but it is many orders of magnitude under a watt. Still, that cubic meter of solar core doesn't even get to what your oven can do.
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Richard Hull
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Re: Conditions required for fusion to occur

Post by Richard Hull »

Again, thank goodness main sequence stars are so terrible at doing fusion! It allows them to burn for billions of years. It is great, and a Godsend that energy based, controlled fusion seems impossible to do on earth. If it were easy, the universe would have had a very short lifespan.

Fissile matter has a store of long trapped ultra-supernova energy just itchin' to be released. No match needed, just bring the stuff close together at room temp, no magnetic fields needed, no vacuum needed, no containment needed, just some shielding and some water filled tubing around the matter to absorb the heat and radiation.

The very first small fission reactor designed to produce controlled power to heat water and figure criticality issues was first run in late 1944 only 6 years after the discovery of fission, itself!! It was called the "water boiler" and run at Los Alamos for a couple of months. Future variants were run for 20 or more years as small test reactor units.


https://www.atomicheritage.org/history/ ... er-reactor

The above film about the water boiler experiment is great! Friedlander talks about their having to manually work with intense reactor produced gamma only sources equivalent to two kilograms of Radium!!!!!


Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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