Reply To: General thought on old coal mines.

[jamesr]

QuantumDot wrote: On the Wikipedia page about DPF it says that, the ones that are larger in the MJ, MA range have pinch’s that last milliseconds, but i didn’t see what experiment that it was referring to and if they do exist does that mean that somewhere the right equipment exists, do you or anyone know? with the improvements that have already been made so far the millisecond confinement time with megawatts of input power look very good.

“These critical phases last typically tens of nanoseconds for a small (kJ, 100 kA) focus to around a microsecond for a large (MJ, several MA) focus”
http://en.wikipedia.org/wiki/Dense_Plasma_Focus

Large devices like the PF-1000 in Poland have been operating for years. The image at http://www.intimal.edu.my/school/fas/UFLF/ show the scale of the machine. They do not achieve a very dense focus though compared to smaller devices, and so the triple product of density*temperature*confinement time needed for appreciable levels of fusion is not as high.

More details of the scaling from kJ to MJ devices based on the Sing Lee model can be found at http://www.plasmafocus.net/

The size of FoFu-1 was calculated to be near optimal. When they switch to the pB11 from deuterium the electrodes will need to be swapped out for even smaller ones as I understand it.