Talk-Polywell.org

JoeStrout wrote:

pstudier wrote:I guess we can argue theory forever, so why not show the experimental data. What is the electron density over space, and how was it measured?

Go get a copy of Krall et al. (1995). It will of course explain it in much better detail than I could summarize here.

Nothing newer than 12 years ago?

pstudier wrote:Nothing newer than 12 years ago?

No, not at a technical level — the research was under a Navy publishing embargo for 11 years, remember? The IAC paper and the Google video give the more recent results in broad strokes, but there have not yet been any technical papers since before the embargo.

Can anyone connect up with Dr.Krall?

I don't know if this is the right part of the forum to ask this on, so if the forum admin sees fit to move it, that's fine OK.

I have been looking at the IEC (polywell) situation and note something I am unsure about.
Robert Bussard is not a young man. Yet he seems to be the sole physicist mentioned in the stuff I have read so far. Tom Ligon is mentioned as an advocate, but his background is biology.
Are there any other physicists (known to list members) who are involved in the polywell research?
I note the Uni of Wisconsin has a small unit which is designed to brew neutrons. I am not yet knowledgeable enough to discern differences or similarities between UWi and Bussard's IEC.
Regards,
Tony Barry

It seems UWi uses straight electrostatics to confine the plasma, and has a "real" inner grid made of wire which provides the collection point for the fusing electrons ; whereas the polywell uses magnetic fields to provide part of the containment system, and the inner grid of the UWi system is replaced in the polywell by a mid-grid which is at zero potential.

... still reading ...
Tony Barry

Tony's basically right; the UW work is on a standard fusor, whereas a polywell machine is sometimes described as a "gridless fusor" — the grid is replaced with magnetically confined electrons. This is a key difference, since in any fusor, ions will strike the grid, quickly destroying it if you try to run at high (anywhere even remotely close to break-even) energies.

UW's IEC Overview is a good place to start getting a handle on the various forms of inertial electrostatic (or electrodynamic) fusion.

Also, note that Bussard isn't the only physicist involved in polywell research; there's Krall as well, though he hasn't been active in it lately. (I'm not sure what he's up to these days, or if he's even still around.)

That's why I'm asking about him. Dr.Krall can help us clear up and reveal technical details, and I recall that he isn't struggling with health issues.

JoeStrout wrote:

pstudier wrote:I guess we can argue theory forever, so why not show the experimental data. What is the electron density over space, and how was it measured?

Go get a copy of Krall et al. (1995). It will of course explain it in much better detail than I could summarize here.

MSimon over on the IEC Yahoo group was also quite impressed with a Japanese paper that experimentally measured the potential well in a different (and perhaps more thorough) manner. I haven't looked that one up myself yet, and I'm sorry to say that I can't find the reference at the moment. But according to Simon, the upshot of it was that it proved the formation and shape of the potential well, at least to his satisfaction.

Just for information:

I keep a lot of links up at:

http://iecfusiontech.blogspot.com/

The Japanese paper on well formation is one of them.

http://wwwsoc.nii.ac.jp/aesj/division/f ... hikawa.pdf

The reason this machine is so confounding is that it operates slightly electron rich. Just like a vacuum tube. The rules are different from those in a neutral plasma.

Here is a link to a number of physics books in pdf about tube technology:

http://iecfusiontech.blogspot.com/2007/07/tubes.html I particularly recommend the Chaffee book as a good place to start.

Operated electron rich you don't get shielding. You get field gradients. And potential wells. In vacuum tube lingo potential wells are called "space charge".

You might want to look up beam power tubes to get some idea of what is going on. The Bussard reactor is a kind of combination magnetron and beam power tube.

Indrek wrote:

pstudier wrote: The video at the first link is totally unrealistic. It shows electrons leaving the cube in the center of the coils going parallel to the field, and then coming back even after they leave the area of maximum magnetic field. Such an electron will go straight off into infinity, just like in a mirror machine.

That's what confused me too at the start. The key is that the coils are also positively charged (so inside is the magnet, the outside shell of a coil is charged using high voltage. So they work like accelerators and attract electrons back in and the magnetic field keeps the electrons from hitting the coils straight on.

Indrek

At what voltage are the coils maintained? If this is what recirculates the electrons, then it will drive away the ions.

pstudier wrote:

Indrek wrote:

pstudier wrote: The video at the first link is totally unrealistic. It shows electrons leaving the cube in the center of the coils going parallel to the field, and then coming back even after they leave the area of maximum magnetic field. Such an electron will go straight off into infinity, just like in a mirror machine.

That's what confused me too at the start. The key is that the coils are also positively charged (so inside is the magnet, the outside shell of a coil is charged using high voltage. So they work like accelerators and attract electrons back in and the magnetic field keeps the electrons from hitting the coils straight on.

Indrek

At what voltage are the coils maintained? If this is what recirculates the electrons, then it will drive away the ions.

The ions are introduced inside the coils/magrid. Actually, from what I've read I believe the gas is introduced inside the coils, and is ionized by the potential of the well(I still don't really understand the injection method). Either method though has the ions orbiting within the magrid. Bussard mentions in passing that any ions up scattering enough in a single pass to reach the magrid will of course be lost.

Indrek wrote:

pstudier wrote: The video at the first link is totally unrealistic. It shows electrons leaving the cube in the center of the coils going parallel to the field, and then coming back even after they leave the area of maximum magnetic field. Such an electron will go straight off into infinity, just like in a mirror machine.

That's what confused me too at the start. The key is that the coils are also positively charged (so inside is the magnet, the outside shell of a coil is charged using high voltage. So they work like accelerators and attract electrons back in and the magnetic field keeps the electrons from hitting the coils straight on.

Indrek

Well, if the grid has to be positive to contain the electrons, then the ions will be repelled by the grid and will not be contained.

pstudier wrote:

Indrek wrote:

pstudier wrote: The video at the first link is totally unrealistic. It shows electrons leaving the cube in the center of the coils going parallel to the field, and then coming back even after they leave the area of maximum magnetic field. Such an electron will go straight off into infinity, just like in a mirror machine.

That's what confused me too at the start. The key is that the coils are also positively charged (so inside is the magnet, the outside shell of a coil is charged using high voltage. So they work like accelerators and attract electrons back in and the magnetic field keeps the electrons from hitting the coils straight on.

Indrek

Well, if the grid has to be positive to contain the electrons, then the ions will be repelled by the grid and will not be contained.

Yep. Except that the ions are contained by attraction to the electrons. Except for the fusion ions which escape from the reaction area due to their high energy.

Zixinus wrote:That's why I'm asking about him. Dr.Krall can help us clear up and reveal technical details, and I recall that he isn't struggling with health issues.

I did a web search and found his last address. His last published paper I can find is from 1997 and the company he started: Krall Associates, 1070 America Way, Del Mar, CA 92014, USA :does not seem to exist any more.

I did find a document sent to Dick Cheney in January 2001 signed by lots of fusion experts, including Krall: Fusion letter (actually sent to Spencer Abraham - see end of that pdf).

I would certainly be willing to help Bussard, Krall and anyone else to see the math gets a through review so it can be published. I studied plasma physics from Krall's book and it would be a blast to get to do it all again. I just don't know where to find them.

MSimon wrote:

pstudier wrote: Well, if the grid has to be positive to contain the electrons, then the ions will be repelled by the grid and will not be contained.

Yep. Except that the ions are contained by attraction to the electrons. Except for the fusion ions which escape from the reaction area due to their high energy.

If one needs a positive grid to attract the electrons to prevent them escaping, than obviously one can not contain enough elections to generate a negative potential well. The electrons repel each other. Indrek's simulations show that one can not even contain single electrons without collisions with just the magnetic field.

pstudier wrote:

MSimon wrote:

pstudier wrote: Well, if the grid has to be positive to contain the electrons, then the ions will be repelled by the grid and will not be contained.

Yep. Except that the ions are contained by attraction to the electrons. Except for the fusion ions which escape from the reaction area due to their high energy.

If one needs a positive grid to attract the electrons to prevent them escaping, than obviously one can not contain enough elections to generate a negative potential well. The electrons repel each other. Indrek's simulations show that one can not even contain single electrons without collisions with just the magnetic field.

Yep. Totally agree. How can it possibly work?

Except the well forms. Has been forming since the 60s.

See the Yoshigawa paper on well formation; a link is on the sidebar at

http://iecfusiontech.blogspot.com/

The Polywell is a simple design. What goes on inside is extremely complex although the results can be explained simply.

Also I think you may be confusing the electric and magnetic fields since they are "generated" by the same structure.

In the start up phase the electrons are not confined by the magnetic field. They are deflected away from the accelerating electrode by the field.