FAQ - The never ending question about fusion and the fusor

If you wonder how/why fusion works, or how/why the Fusor works, look here first.
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Richard Hull
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FAQ - The never ending question about fusion and the fusor

Post by Richard Hull » Mon Sep 09, 2019 7:52 pm

Newbies swim into the forums with a lot of mush in their heads having seen the "star" of fusion in the fusor. The ball of glowing plasma is a characteristic of the physics of the device. Beyond being a stunning object to hang one's fusion hat on, and a piece of inspiring "art" in a picture, the ball in the center of the grid is not a harbinger of fusion taking place. Do not let the pretty pictures lead you astray.

The plasma density in the ball is near zero for all intents and purposes. Very little fusion occurs there ( shown by work done at the University of Wisconsin). The average amateur fusor is a horrid and inelegant misch-mash of electrons, deuterons, fast deuterium neutrals and tramp/trash gases, (with a micro-smattering of fast helium3 atoms, naked protons and Tritons). There are as many as 6 different mechanisms that might be active in doing fusion in a fusor and just as many that hamper and foil any one of the efforts that actually do fusion in a fusor.

Never think of the fusor as a marvelous fusion system. It is a bull headed effort that really does fusion at the cost of tremendous electrical energy losses and wastefulness. I would put it on a par with mining coal by running at the coal face with a car, crashing into it to obtain the much desired coal.

In the finest iterations one might get a micro-watt of fusion energy output per 100 watts of input electricity. This is somewhere in the area of 10e9 to at best 10e8 net LOSS! A billion to one net energy loss in a fusion system is laughable. However we do real fusion and many of us do it not for fusion but to make a small, yet viable, neutron source.

If you have done a good bit of reading here, you will see that the latest spate of tiny fusors can work with reduced voltages at pressures 2,3, or even 4 times what the 6" diameter spheres require and produce decent fusion. Still, terribly inefficient, just less costly to build, but require a bit tighter construction techniques to avoid arcing. Rest assured any idea you might have will end in tears as it has already been tried and failed by others long ago. As of today, fusion in this universe to create net power, is granted only to stars. Nature and physics resist local controlled fusion to a degree that you cannot comprehend. It is a good thing too. Nature does not want the entire material universe full of hydrogen to go off in a grand explosion in a few seconds. Nature uses the physics that makes fusion possible to prevent it!!

99.6% of those who have done fusion here have done it to say they have done it and never do research with the finished fusor to improve its performance. About 0.3 % are after a useful neutron source and couldn't care beans about fusion beyond a means to an end. The remaining 0.1%, usually only one or two people at any given moment, are "pushing the envelope".

If one is attempting to create a dense ionized plasma involving the bulk of the deuterium, they are doing hot fusion or are throwing energy away at a prodigious rate.

Fusion is easier to do than fission, requiring far less expense and effort. However, fission and fission alone is the real net power producer. Fusion energy is a grand dream and forlorn hope, a carrot hung out in front of the donkeys to keep them moving along.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Re: FAQ - The never ending question about fusion and the fusor

Post by Xiaoyi_Sun » Thu Apr 01, 2021 3:10 am

The plasma density in the ball is near zero for all intents and purposes. Very little fusion occurs there ( shown by work done at the University of Wisconsin).
I am interested in this research and I am wondering can you post the name of the paper related to the work done at the University of Wisconsin?

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Richard Hull
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Re: FAQ - The never ending question about fusion and the fusor

Post by Richard Hull » Thu Apr 01, 2021 6:20 am

The U of W paper URL or PDF that noted the experimental fact that almost no fusion occurs in the center is buried in ancient postings either on the Intranets iteration or on the very early fusor.net postings in the early 2000's. If you wish to ferret it out you may. I do not have it at hand. Check for some of their papers at.....
https://iec.neep.wisc.edu/

I believe this was the peer reviewed paper.

S. Krupakar Murali, B.B. Cipiti, J.F. Santarius, and G.L. Kulcinski, “Study of Fusion Regimes in an Inertial Electrostatic Confinement Device Using the New Eclipse Disk Diagnostic,” Physics of Plasmas 13, 053111 (2006).

It is certainly possible that the glowing center may represent, within its pitifully small volume, the highest unit volume fusion in the fusor. However, the above paper shows that the bulk of almost all the actual fusion within the reactor happens outside of the central grid, within the huge volume of velocity space within the reactor. Much has been written here on this topic.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Re: FAQ - The never ending question about fusion and the fusor

Post by Nicolas Krause » Tue Apr 06, 2021 6:49 pm

https://www-tandfonline-com.ezproxy.lib ... FST05-A857
This paper gives a good overview of their work and setup, also a good place to start. The following information from the introduction refers to what Richard is mentioning.
Fusion concepts that rely on electrostatic focusing of ions into a dense core in spherical or cylindrical geometry are called inertial-electrostatic confinement (IEC) fusion systems. Although the original concept relied upon beam-beam fusion reactions in the core, fusion reactions in present experiments occur mainly as beam or charge-exchange neutral interactions with background neutral gas. The limited core density stems from the finite transparency of the cathode grid and the relatively high operating pressure (1-10 mtorr) of the background gas,which lead to frequent charge-exchange reactions.

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Re: FAQ - The never ending question about fusion and the fusor

Post by Xiaoyi_Sun » Wed Apr 07, 2021 4:16 am

Thank you guys for the replies, that is really helpful...

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