Publications

Experimental observation of plasma formation and current transfer in fine wire expansion experiments

Deeney, Christopher D.; Sinars, Daniel S.; Deeney, Christopher D.

When several kA pulses are passed through single, fine 25 {micro}m diameter wires, the wire material heats, melts, vaporizes and expands. Initially the voltage across--and current through--a wire increases until an abrupt voltage collapse occurs. After this collapse the voltage remains at a relative small value while the current continues to increase. In order to understand how this early time behavior may affect the subsequent implosion, small-scale experiments at Cornell University's Laboratory of Plasma Studies concentrated on diagnosing expanding single wire dynamics. X-ray backlighting, interferometry and Schlieren imaging as well as current and voltage measurements have been employed. The voltage collapse has been attributed to the formation of plasma around the wire and a transfer of current to this highly conducting coronal plasma. Interferometry has confirmed the plasma formation, but the current transfer has only been postulated. Subsequent experiments on the Z-Facility at Sandia National Laboratories have produced impressive x-ray yields etc.