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Posted: Tue Jul 08, 2008 4:07 pm
by TallDave
and the fact that Bussard was confused about the dramatic difference between electron density and neutral density
Nah, I think that was just a typo. In one place he talks about neutral density and ionization, in another he has an incomplete sentence about electron density ratios and arcing. He probably just mis-pasted his parenthetical.

Correct me if I'm wrong, but both neutral and electron density would presumably affect arcing.

Posted: Tue Jul 08, 2008 4:49 pm
by Art Carlson
TallDave wrote:
and the fact that Bussard was confused about the dramatic difference between electron density and neutral density
Nah, I think that was just a typo. In one place he talks about neutral density and ionization, in another he has an incomplete sentence about electron density ratios and arcing. He probably just mis-pasted his parenthetical.

Correct me if I'm wrong, but both neutral and electron density would presumably affect arcing.
Given full liberty to assume typos, can you paste together a coherent and plausible picture of the relationship between cusp confinement, recirculation, and arcing?

Posted: Tue Jul 08, 2008 4:58 pm
by MSimon
Art Carlson wrote:
TallDave wrote:
and the fact that Bussard was confused about the dramatic difference between electron density and neutral density
Nah, I think that was just a typo. In one place he talks about neutral density and ionization, in another he has an incomplete sentence about electron density ratios and arcing. He probably just mis-pasted his parenthetical.

Correct me if I'm wrong, but both neutral and electron density would presumably affect arcing.
Given full liberty to assume typos, can you paste together a coherent and plausible picture of the relationship between cusp confinement, recirculation, and arcing?
1. Electron loss is the (first order) dominant energy loss mechanism. It is reduced by:
a. Magnetic confinement
b. Recirculation (Oscillation)

2. Confinement is required to maintain a particle density in the reaction space sufficient to provide useful amounts of energy given the limited density possible outside the reaction space.

What is the reality? I await further results.

Posted: Tue Jul 08, 2008 5:07 pm
by TallDave
Art Carlson wrote:
TallDave wrote:
and the fact that Bussard was confused about the dramatic difference between electron density and neutral density
Nah, I think that was just a typo. In one place he talks about neutral density and ionization, in another he has an incomplete sentence about electron density ratios and arcing. He probably just mis-pasted his parenthetical.

Correct me if I'm wrong, but both neutral and electron density would presumably affect arcing.
Given full liberty to assume typos, can you paste together a coherent and plausible picture of the relationship between cusp confinement, recirculation, and arcing?
Heh, well I can try.

Cusps are squeezed nearly closed (or at least give a bad angle to electrons trying to leave) at beta = 1, so we get an electron density ratio inside versus outside of 1000:1; the 1/1000th outside are continuously recirculating back inside because the cusps are friendlier to electrons returning. Assuming there aren't too many neutrals floating around, this outside electron density is low enough that no arcing to the wall occurs, while the interior density is high enough for fusion.