Why do fusors work?

[Dan Tibbets]

Concerning transparent grids, if they were transparent/ vertual, the ions could pass back and forth indefinitely in a connectionless plasma, or a plasma that maintained a mono energetic temperature. The would traverse the potential well indefinitely. The problem is that a collisionless plasma is useless. You cannot have fusion without collisions. And scattering Coulomb collisions will always occur more frequently than fusion collisions. You can come close with D-T fusions at ~ 100 KeV (~ 1:10 ratio) and with D-D fusions at several MeV. The problem with the D-D though is that at these energies losses are increasing faster than the fusion rate. Bremsstrulung in particular is a problem as it increases faster than the fusion crossection curve once you are over several hundred KeV. Also other unwanted nuclear reactions become more prevalent.. Even if you can recover the Bremsstrulung losses through a heat engine (steam plant) you can only reach ~ 30% efficiency, and that is not enough to overcome the fusion/ Bremsstrulung rates at these temperatures. If you had a 99% heat to electricity conversion efficiency, thing would change a lot. Concerning conversion, if you have to accelerate your ions to 2 MeV, and you get ~ 3 MeV per fusion, , you would get ~ 5 MeV of heat, converted at 30% efficiency would result in ~ 1.5 MeV of output. This is less than the energy you put into the fuel ions. You are losing ground. Because of this there are compromises needed. The best monoenergetic temperature would probably be somewhere around 100 to 200 KeV. Bussard preferred ~ 80 KeV, but I don't know if he was planing on only burning D-D or if this incorporated recovering the tritium and helium 3 and also burning those secondary fuels where the three fusion crossection curves are different.

Back to thermalization. Upscattering will result in the ions reaching the wall and losing their energy. I don't know the relative rates but it would not be far behind grid collisions, perhaps 1-2 orders of magnitude at best, depending on the temperature - again there would be a compromise between the fusion and scattering crossections. If the gridded fusor can reuse the ions for ~ 10-20 passes, then with a transparent/ virtual/ magnetically shielded cathode (or anode with an Elmor Tuck Watson fusor), them perhaps 100-2000 passes might be achievable. Bussard , etel found that ~ 10,000 or more ion passes was the minimum required ( or > ~ 100,000 electron passes). ~10-100 times more would be needed to achieve good fuel burn up. You need something more. . Without going into details, this is embodied in the Polywell design. There is also a group of MIT graduates types working on something similar.

Dan Tibbets

[Dan Tibbets]

Steve Sesselmann, It is generally accepted that we line in fairly flat space. If we lived near the event horizon of a black hole the relative fusion rates would be faster away from the black hole from out perspective, but I'm not sure how we would interface with this. As far as speed, we are traveling at ~ known velocities relative to distant galaxy clusters, and our movement with the expansion is also known and at least for nearby (several billion light years) the speeds are not reletivistic. . Perhaps if we located a reactor on the opposite side of the observable universe, it would have a much faster percieved fusion rate. But, the transport of the electricity to us might ba a problem.

As for the rest mass/ energy of a proton (or neutron?), if this is actually a result of a velocity in a different frame of reference, I do not see the link to our reality/ reference frame. To a photon the rest mass / velocity in some other dimension may be zero or very close to it. but to increase the fusion rate of these particles from our perspective we would have to speed our selves up, not slow the particles down- that would be decreasing their energy to almost nothing ( in our reality/ frame of reference) and thus eliminating any energy yield for us.
Mmm... I might be knocking on the door, but I don't know what is behind it and I don't have a key.

Dan Tibbets

[Carl Willis]

I feel this thread has been given a fair shake, but the chain of responses is mostly characterized by word salad. We've got wide-ranging and off-topic speculation. A dearth of credible references, or new theoretical developments closely accountable to observed reality. And more than a lion's share of barking-mad nonsense.

It's never been my understanding that off-the-cuff scifi-convention bathroom banter amounts to "Theory." We don't have a general banter forum. (That idea has been proposed, and shot down, several times.) If we did have such, that's where 90% of this thread would belong. But as it is, this is a "Theory" forum.

To get to the point at last: thread's closed.

-Carl