Gas-Heating Effect on Plasma Resistivity

Measurements of hydrogen-plasma resistivity were made under conditions where the dominant loss mechanism was electron-neutral collisions. Three-inch-diameter tubes with electrode spacings ranging from 2–22 in. were used. Measurements were made at 15 and 22 kA, 56-μsec pulse duration, and pressures of 0.5, 1.0, and 5.0 Torr. Electron-density and temperature measurements were obtained from Stark-broadening and line-intensity-ratio techniques. The predicted resistivity was calculated from electron-proton and electron-neutral collisions and compared with the absolute resistivity calculated from the voltage-current measurements. The gas-temperature rise was determined from the resistance difference obtained from the two calculations. The energy expended in gas heating was determined to be 2.4%–4.2% of the input energy.