Effect of anode and insulator materials on plasma focus sheath (pinch) current

Abstract

Plasma sheath (pinch) current in a low energy (2.2 kJ) plasma focus device was measured fur different anode and insulator materials. Among the anode materials, the highest sheath current was observed with tungsten and the lowest with aluminum. Among the ceramic insulators the maximum plasma sheath current was obtained with quartz and the minimum with alumina. The computed high Z (atomic number) impurities in plasma sheath, however, were least in the plasma focus with alumina insulator. None of the nonceramic (plastic) insulators produced neutrons, as the plasma sheath was nonuniform and was highly contaminated with impurities.