The effect of insulating coatings on exploding wire plasma formation

Substantial increases are reported in the expansion rates of exploding, den se wire cores under conditions simulating the prepulse phase of wire array z-pinch experiments [R. B. Spielman , Phys. Plasmas 5, 2105 (1998)] using w ires with insulating coatings. The insulation apparently allows additional wire heating by delaying the formation of plasma around the wires. Once pla sma is formed it terminates significant current flow in the residual wire c ores. This effect is demonstrated for 25-mu m diameter W and 25-mu m diamet er Ag wires. (C) 2000 American Institute of Physics. [S1070-664X(00)00102-6 ].