Computing plasma focus pinch current from total current measurement

The total current I_total waveform in a plasma focus discharge is the most commonly measured quantity, contrasting with the difficult measurement of I_pinch. However, yield laws should be scaled to focus pinch current I_pinch rather than the peak I_total. This paper describes how I_pinch may be computed from the I_total trace by fitting a computed current trace to the measured current trace using the Lee model. The method is applied to an experiment in which both the I_total trace and the plasma sheath current trace were measured. The result shows good agreement between the values of computed and measured I_pinch.