Factors affecting the expansion of single 25 /spl mu/m wires driven by a current rise rate of 10/sup 10/ a/s for 1100 ns

Summary form only given. In previous work (Sinars et al., 2000) we investigated the significant impact of thin insulating coatings on the explosion of 25 /spl mu/m Ag and W wires driven by a pulsed current source with a rate of current rise of 10/sup 10/ A/s per wire. This range is similar to the prepulse conditions of wire-array experiments on the Saturn and Z accelerators at Sandia National Laboratories in Albuquerque, NM. Our studies have found that most of the energy deposition in wires under these conditions occurs during an initial resistive heating phase lasting <100 ns. This phase is terminated with the collapse of the voltage across the wire. The effect of the insulating coatings is to postpone the voltage collapse, thereby significantly increasing the amount of energy deposited during the resistive heating phase. The increased energy deposition causes a significant increase in the observed expansion rate of the dense wire cores as they explode. In recent experiments, we have found that insulating coatings have a similar effect on the expansion of 25 /spl mu/m Cu, Au, and Pt wires. In addition, we will discuss the effect of other factors on the behavior of exploding wires, such as (1) thin metal coatings, (2) differences in the initial purity or structure of the wire material, and (3) different current driver pulse shapes.