Thanks Dan, I'll have to struggle through that at some point this week. BTW in case you didn't see, Simon left another link which may be helpful.
Art -- Sure, except you predict ion currents and the hot spots are on the casings, not the wall. But you don't care, and neither do I, so...
bcglorf -- here's the point I was trying to make, probably not very well:
rnebel wrote:Your logic is flawed. Ions do not have to move into the cusp at the same rate as electrons in order to maintain quasi-neutrality. If ions and electrons leave at the same rate that they enter (and this is true anywhere in the plasma) then quasi-neutrality can maintained. They simply have to leave at the same rate they enter, and it doesn't have to be the same for ions and electrons
At the cusps the electrons are near the bottom of their potential well and highly energetic, the ions near their top and sluggish. Electrons bounce around the bottom, recirculating and being lost to cross-field diffusion, while relatively few ions make it over the top. Bussard deliberately set out to build a machine in which electron losses would dominate. Did he succeed? Maybe. Rick seems to think so. Does it scale well? Who knows. Rick has said he doesn't know how cross-field diffusion scales in these machines.
There's a lot that seems to be poorly understood. Frankly, I won't be shocked if they never get WB-8 past arcing problems.
n*kBolt*Te = B**2/(2*mu0) and B^.25 loss scaling? Or not so much? Hopefully we'll know soon...