why just one potential well?

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
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mtrusty
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why just one potential well?

Post by mtrusty » Mon Sep 15, 2003 12:53 am

I'm just starting into learning about fusors but I have an amazingly stupid question.

My basic understanding is that fusors work by creating a deep enough potential well to keep ions ocsilating back and forth through a central area. Add fuel to the center, and if you've gotten your magnitudes correct you'll achieve fusion.

Unforunately the apparatus to create the potential well also blocks the paths of the ions, robbing energy from the system.

So my probably amazingly ignorant question is.. why not multiple potential wells? Orientate them around a central point, wells overlapping so the center point has a higher potential than any of the given generators. Ions might initially go to one of the genetrating wells , but their orbits should be drawn towards the stronger, artifical one fairly rapidly. So long as they are caught by the 'artificail' well at a faster rate than lost to impacts from the generator apperatus,you should have a system with a significantly reduced loss due to non-productive impacts.

Not claiming I'd expect a perfectly efficent system. I'd suspect as you reached a certain density of ions an exponential increase in cost to introduce more.


Am I making any sort of sense, or merely sound like a bored unix programmer who has had MS software forced upon him for too long? I don't expect my idea to be correct, just hoping it'll expose enough defects in my knowledge that I might learn something.

3l
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Re: why just one potential well?

Post by 3l » Mon Sep 15, 2003 1:01 am

Hi:

The multple well has not been tried in a long long time.
Richard Hull was gona revive it....I had plans to revive but...
The problem is some how you got to get the ions to behave themselves...ie go thru the holes and not hit the grid.
Even a perfectly aligned two grid system has collisions with the grid. More grids more losses on the regeneration of ions.
The rest of your hypothesis sounds very familliar.
It is the rational behind pulsing....you limit the loses by doing a large pulse into a small area....Multiple wells are created by different kinetic velocities of the deuterons relative to how close to the geometric center of the grid they are located. Think perfectly spherical wells of repelling deuterons mashing into empty space untill they stop. on the outside of the grid they have the most energy to cause compression and at the center the vast numbers of stopped ions create the density and pressure to fuse.

Happy Fusoring!
Larry Leins
Fusor Tech

grrr6
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Re: why just one potential well?

Post by grrr6 » Mon Sep 15, 2003 1:54 am

The potential wells occur as a byproduct of fusor operation, not fusor operation as a result of potential wells.

The multiple potential wells are postulated to occur as a sort of oscillation when electrons are attracted to the virtual anode, creating a virtual cathode attracting ions etc. The problem is that electrons have about 1/4000 the mass of a deuteron, meaning that the electron flight times are really short compared to the ion flight times so that the virtual anode persists for much longer duration than the virtual cathode, so i think the gain is small. If you could use high mass negative ions instead of electrons it could probably benefit more, although this would be very difficult to impossible to implement. Sorry for the super long sentence.

mtrusty
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Re: why just one potential well?

Post by mtrusty » Mon Sep 15, 2003 2:37 am

Thanks. I already figured that if the ions didnt go for the sweet spot quickly you'd windup with a less efficent system from the extra grids.

So at this point, the only holy grail for fusors is somehow isolating the ions from the grid, without otherwise impeding their progress?

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Frank Sanns
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Re: why just one potential well?

Post by Frank Sanns » Mon Sep 15, 2003 2:06 pm

The multiple potential well has been part of the evolution of my fusor project for a while now. I think it is a great idea that has not been fully explored.

A few of my earlier posts were from my soapbox and were about the possibilities of resonance inside the fusor. The idea of resonance is to sustain the kinetic energy of the ions (i.e. deuterons) to give a higher probability of collision. In fusion, that is typically thought of in terms of ONE LOCATION (in the poissor) and ONE PASS. Resonance with a single inner grid will give the chance of a second or a third or more passes.

Now here is the cool part.....Fission relies on neither. It relies instead on shear number of chances of collisions by using a large number of heavy atoms to intercept neutrons to stimulate another fission.

The Idea of resonance with multiple grids has the potential (excuse the pun) to work at efficiencies never seen in a fusor because of a huge leap in efficiency. This would be achieved by having a large UHV chamber with hundreds or thousands of inner grids that would all be tied to a central RF Power supply. The frequency would be selected so that if a deuteron would not collide inside one of the inner grids, then it would maintain its kinetic energy almost in its entirety and go on to the next grid and the next and the next. This configuration gives MUTIPLE LOCATIONS and MULTIPLE PASSES. The size of the chamber would be dependent on the operating parameters but there would be minimum CRITICALl SIZE for Fusion just like there is a CRITICAL MASS for Fission.

From all of my fusor experiments so far, it is clear to me that such a radial departure from normal thinking will be required to solve the fusion dilemma.

Frank S.

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Re: why just one potential well?

Post by guest » Tue Sep 16, 2003 2:06 pm

"Multiple Potential Well Formation: Ion confinement time in the hot plasma can be significantly increased via the formation of a series of multiple potential wells inside the cathode-gird. These "virtual wells" appear as "virtual" anodes and cathodes to the ions, confining them but not absorbing them like the "real" cathode-grid. With this formation of wells the only loss mechanism for the ions is upscatter (an interaction in velocity space, not physical space) and fusion. These wells, modeled with computational codes and observed experimentally (described below), form due to a complex interaction between the ions circulating through the cathode-grid and electrons, emitted as secondary products from the cathode-grid when an ion is absorbed and from ionizations of the background gas inside the cathode-grid."

http://www.lanl.gov/projects/pfxi/ecwg/iecwp.html

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Frank Sanns
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Re: why just one potential well?

Post by Frank Sanns » Fri Sep 19, 2003 10:07 pm

High bull factor stuff written by somebody at LANL looking to get or justify funding. Seems that throwing in a couple of noun strings to sound like you know what you are talking about gets you funding. Go figure.

Frank

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