ZT-40M current risetime study

A study of discharge risetimes was undertaken in the reversed-field pinch (RFP) experiment, ZT-40M, to obtain guidelines for future larger and slower experiments. The electrical circuits allowed nominal risetimes of 0.25 to 1.5 ms and peak toroidal currents were less than or equal to 180 kA. For the longer risetimes optimized operation occurs at higher fill pressures which leads to larger radiation losses, a larger poloidal flux consumption, and a larger fraction of the energy input being lost by the time of peak toroidal current