Plasma properties of kiloampere discharges

Plasma properties and characteristics that are of interest to high-current switching devices have been investigated. Peak pulse currents up to 80 000 amperes have been used to generate dense plasmas in linear glass-metal diodes. Two tube diameters, 3 and 7.5 inches, have been studied. In the case of the 3-inch, diameter diode, the electrode separation was varied from 10.6 to 25.1 cm. Hydrogen gas was studied in the pressure range from 0.5 to 40 torr. Electron densities and temperatures have been determined using spectroscopic techniques. Densities were found to be in the 10¹⁶to 10¹⁷cm^-3range. Plasma resistivities have been datermined from a knowledge of the density and temperature. The observed dependence of resistivity on current and pressure is discussed and the results are compared with resistivities obtained from tube-drop measurements. The effects of impurities and instabilities are also discussed.