Wire Ablation Plasma Source Studies at Sandia National Laboratories

Experiments are underway to investigate wire ablation plasmas as potentially tunable sources for applications such as intense electron beam transport and focusing. For these studies, one or more fine wires (100 micron diameter) are driven by a microsecond long, capacitive discharge (80kA, 100kV) to generate a plasma. High resolution visible/uv spectroscopy is used to spatially and temporally characterize the plasma throughout the pulse. Measured lineshapes and intensities are compared with time-dependent, collisional-radiative calculations to obtain plasma densities and temperatures. Changes in drive current, wire geometry, and materials are studied to determine the extent to which ablation plasma parameters can be controlled. Results are compared to MHD calculations and scaling laws for plasma mass ablation rates from wires.