Factors affecting energy deposition and core expansion in low current single wire experiments

Summary form only given. Single wire experiments have been performed on Cornell´s new Low Current Pulser 3 (LCP3) which consisted of a 220 nF capacitor charged to 20 kV. The capacitor and wire holder were connected in series through a switch and external, variable inductor used to control the current rise-time. This external series inductance was adjustable in five steps from 0.2 /spl mu/H to 2 /spl mu/H allowing the current rise time to be varied from 5 A/nsec to 50 A/nsec. Each wire was heated through melting and vaporizing phases by the current pulse and began expanding. Energy deposition, reproducibility and expansion rates were measured as functions of the current rise rate. These results indicate better energy deposition and higher expansion rates with faster current rise rates. The connection method and sign of the radial electric field at the surface of the wire were also varied. Preliminary experiments with copper indicate that energy deposition becomes independent of current rise rate with better wire-electrode connections.