Talk-Polywell.org

I should have gone ahead and quoted him: there will probably be about an order of magnitude density ratio between the anode region and the central plasma n/n_0 ~ 0.1. The ratio would probably be lowest for cases with a large volume of field-free plasma, narrow anode gaps and low neutral gas pressure...

That seems like a decent treatment to me, that business with mc^2 is very clever. It's counterintuitive that the space-charge voltage is worse than inversely proportional to rho_e. But I think I see why: the area of the (point) cusp goes with 1/B , but the electron density goes with B^2, assuming be...

I have explained why I don't expect any recycling, and nobody has presented a counter-model in any helpful degree of detail. If you can do that, great! Ok, let me see if we are on the same page: http://x87.xanga.com/5238535718108232272013/m183200974.jpg The graph is in radius from the center of the...

Yeah, the trouble is that if the plasma actually shoves the magnetic field lines back at high beta, then they might get displaced so that they impact the toroidal electrodes. The best part is that since the permanent magnets can be run in steady state :D it might be possible to burn out the backgrou...

http://www.jetpletters.ac.ru/ps/1535/article_23489.pdf This is a nice summary of an electrostatically-plugged cusp machine (albeit a toroidal cusp.) It seems like it would make a nice primer for polywell physics. Page 2: "The escape of the electrons from the system along the magnetic field is blocke...

Sounds like it's time for someone to ask Indrek to do some more of his amazing field visualizations!

I'm also an undergrad, wanting to do some polywell-related research. I don't think I have the resources to do an actual experiment at my school, but I think I might end up doing a programming/simulation project. I have an idea about trying to determine collective effects using a smaller number of pa...

Wow, in that PDF he claims to have done a PIC model that shows that the machine should work. I'd like to see more of that.

Alright! Good news at last! I am itching to see more details, too.
Way to go Dr. Nebel & co.!

Art: yes, the field lines hit the walls, but if the electrons are low-energy (like the ones produced by ionization of neutrals at the edge of the plasma) then they will not have sufficient energy to reach the wall.

Ok, so you are saying that the sheath thickness determines the minimum size that the cusp loss hole can be, be it line or point? (And that the sheath thickness is driven to be about the hybrid Larmor for some reason or other.) I buy that. But won't the plasma expand until the sheath is very close to...

Art: I'd like to see a bit more about how Haines derives his conclusions about "recirculation." I'm a bit skeptical that his assumptions apply to our case. Dolan's literature review from '94 came to a different conclusion.

To continue with the questions about the shape of the plasma, what I'd like to do (or see someone do, anyrate) is figure out what the flux surfaces look like that bound the plasma in a polywell. Despite the fact that the coil cans are supposed to be conformal, there must be some flux surfaces which ...

That's very interesting. I'm all for tokomaks if they can work.

MSimon: is there any way we could make a sticky at the top of the "theory" forum to house links to relevant documents, or possibly citations of documents that are not available electronically? DW: that's what you woul think. Apparently, nobody actually tried Bussard's exact idea, and we don't know e...