Modeling of high current water discharges for high energy transfer pulsed power systems to determine steady state conduction resistance

Abstract

Summary form only given. Experimental waveforms obtained from the Z-20 water switch test bed at SNL, and PITHON at Titan-PSD, are matched with their respective circuit models to determine the equivalent inductance and conduction resistance of water switches. In both experimental cases the waveform match is very good and the resulting inductance and conduction resistance values consistent. The conduction resistance is the single channel resistance per unit length of switch gap after the arc is established and in this analysis is in the range: 0.064 O <R (/spl Omega//cm) <0.080O. The waveform match is very good and the resulting inductance and conduction resistance values are consistent between the various experiments. A comparison of the experiment to models for a series of waveforms with several different switch configurations will be presented. The conduction resistance for all of the comparisons falls within the above range of resistance values. The details of the switch model and the technique used to determine the resistance values will be presented. We also present the energy transfer efficiency as predicted by each switch model. A computer model constructed by Thomas H. Martin that includes more plasma physics is based on the Braginskii physics model of spark channel formulation. In this computer model, several parameters need to be specified such as the number of channels in the discharge, the length of the channel and the conductivity of the medium. We discuss experimental results that help in selecting these parameters. An assessment of the sensitivity of changes in the elements of the Braginskii-Martin equations of the water spark channel formation is presented and compared to the data.