Talk-Polywell.org

To pick a nit here, the volume inside any conducting shape is of uniform potential. If the sphere is not conductive, then an asymmetric charge on the sphere can cause gradients inside. Fair enough. All the components in this case are conducting (perhaps I should have specified), and they are also p...

I think you're confusing Coulombs and Volts. Coulombs are absolute. But I'm thinking in terms of volts, and electric field deriving from a difference in volts between 2 shell or grid levels. The magrid has a potential higher than the trap grid. both magrid and trap grid have a potential much lower ...

I doubt it. You never know with quantum mechanics, but... ...in gas kinetics, we do all our calculations assuming two-body collisions. Three-body collisions are supposed to be so rare that they can be neglected. This becomes less true for charged particles (Coulomb collisions) but what you're talkin...

Perhaps I described it a bit sloppy. Without the grid between the magid and the outer shell, the electrons outside will see the magid will see the magrid at a MV or so lower electrical potential than the surrounding and rush for the higher electric potential. A trap grid isn't needed for direct con...

The electrons are hot at the edge and cold in the core, which could result in an annealing effect, but the edge isn't where it would happen. I'm pretty sure edge annealing is just for ions. jmc does a good job of explaining it in his link. I posted on this topic a while back, describing what I under...

1) They don't see the direct conversion sphere. That's why you need a trap grid, so that once the alpha particles have passed it on the way to the wall, it attracts them and decelerates them to a stop. Naturally, if any electrons get past the trap grid, they get fired into the outer wall at ~2 MeV. ...

Well, you've at least got the electric field from the electrons in the wiffleball. Since we're charging up the magrid to increase the well depth for the ions (we are, right?), I'll assert that the direct conversion charge will also be felt. They're both essentially the same geometry. The magrid is ...

I think you need a negative grid between the magid and the direct conversion shell. Otherwise electrons outside the magrid will see the direct conversion shell and zip straight for it. It doesn't matter what the charge on the outer shell is - not to the electrons, anyway. Once they're inside it, th...

If they are running one pulse, 0.1s long, per hour, that would be fantastic, and would provide enough information to validate or refute Dr. Bussard's theories. It would indeed be fantastic. I had the impression that the lack of cooling limited them to a couple of shots per day; I can't remember wha...

Also note that since it is an uncooled pulsed machine (last I heard), if you're sitting there taking data all afternoon you probably aren't running at fusion conditions. Not to say they can't - there's a lot you can learn from low-power experiments even if the pulsed power capability is there - but ...

I've done BOE calculations on atmospheric ion propulsion. Using ECR or something to provide ~0.004% ionization (~0.06% single ionization per molecule) fairly evenly throughout a 300 kg/s airstream (reasonable-sized turbofan @ M=0.9 and 40,000 feet), and applying ~10 kV of accelerating potential, you...

Yes, there is. All you have to do is not use trap grids, and they'll smash straight into the outer wall and generate heat. Of course, this exacerbates the first-wall problem, but only by a factor of maybe 5. Considering the usual efficiency of converting electricity to heat (pretty much 100%), plus ...

The only problem is cooling. If you can get rid of the waste heat from the reactor without dumping hydrogen (pipe it into the engines via a SABRE-style preheater after the compressor? Or just dump it to the air somehow), you're good. The only thing fuel does besides heat the airstream is add a littl...

Don't I remember a history channel episode where the air force already built a nuclear powered jet back in the cold war? I think they piped liquid sodium coolant directly to the jet engines which ran off the heat of the reactor. Of course they had to have a lead lined cockpit and irradiated the air...

Yeah, I saw that article a while back. It's interesting, all right, although the writer seems to have had some trouble trying to describe how it works... Is DC/AC and AC/DC conversion okay at 1 MHz? POPS might be able to produce low-bias AC with proper choice of floating voltages, but I need DC for ...