Water switches impedance from screamer circuit model and experimental waveform match

Abstract

Experimental waveforms obtained from the Z-20 water switch test bed at SNL, and PITHON at PSD, are matched with their respective circuit models to determine the equivalent inductance and conduction resistance of water switches. These circuit models and three water switch models, available in SCREAMER, were used to obtain a match to the experimental water switch breakdown current waveforms. In both cases the waveform match is very good and the resulting inductance and conduction resistance values consistent. The equivalent conduction resistance obtained is in the range: 0.064/spl les/R (/spl Omega//cm) /spl les/0.080, single switch per unit length of switch gap. This match was obtained, with a series of experimental waveforms, out of shots with positive and negative enhanced electrodes from both machines. Excellent experimental to model match was found, for a full series of waveforms, all within the range of resistance values. A series of waveforms are shown together with the details of the switch model and the technique used to determine the resistance values.