Interesting entry in Do The Math Blog about Fusion.

[Lerner]

Hi Maya,

You can get a lot of answers out of our published papers. Forces have to be balanced, but not pressures. A DPF generates enormous pressures through the pinch effect, concentrating currents in the tiny plasmoid. The hundreds of MG (mega-gauss ) fields already observed are far above those that could be generated by a magnet. But pressures applied on tiny volumes require only modest forces. And the forces are only applied over very short periods of time–in our machine a few microseconds. (Our machine’s vibrations do have an inconvenient ability to unscrew just about anything! We are therefore elimanting screws.) As for neutrons, a future DPF gnerator would produce 5MW of net power from about 12 MW of total fusion power. Neutron power from secondary reactions will be only around 24 kW and in the form of low-energy neutrons that do little damage.

[Lerner]

Actually, what has to balance is force averaged over time to get zero net accleration. In a future generator, we expect 10 GG fields in a roughly 10 micron radius plasmoid lasting several ns and repeated 200 times a second or so. You do the math. It works out to average forces of around a kN–not so much. In other words, huge pressures in a very tiny volume for a very short time works out to not very much average force. But you get good burn up and net energy.

[Maya]

Lerner wrote: Actually, what has to balance is force averaged over time to get zero net accleration. In a future generator, we expect 10 GG fields in a roughly 10 micron radius plasmoid lasting several ns and repeated 200 times a second or so. You do the math. It works out to average forces of around a kN–not so much. In other words, huge pressures in a very tiny volume for a very short time works out to not very much average force. But you get good burn up and net energy.

Agreed on these points. What intrigues me most about your approach is the way you are creating magnetic fields, which skirts some serious materials science issues faced in tokamaks.
I’ll read some of those papers and thanks for the pointer.

[Author]

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