Theoretical and computational studies of plasma opening switches

Substantial progress has been made in understanding the operation of plasma opening switches (POS) in support of the Light-Ion Fusion Program at Sandia National Laboratories. Our efforts began with scoping studies using the particle-in-cell (PIC) code, MAGIC, which was written by Bruce Goplen and co-workers at MRC for pulsed-power applications. The version of MAGIC currently at Sandia National Laboratories is supported by Dave Seidel and Tim Pointon. MAGIC continues to play an important role as our studies moved into many different areas. Working closely with Cliff Mendel, we performed initial studies of switches using his fast B/sub z/ concept. Working with Mary Ann Sweeney, Jeff Quintez and Cliff Mendel we performed studies of the effects of plasma density, cylindrical curvature, load impedance, rise time, and emission threshold on switch performance. In addition, we studied B-field penetration, turbulence, anomalous resistivity, and electron heating in plasma opening switches. This work has allowed us to identify the physical mechanisms that are important in the operation of plasma opening switches. Based on our knowledge of the physics we have established scaling relations for comparable switch performance under different experimental conditions. We studied the code requirements for POS simulation and numerical problems in MAGIC andmore » in other PIC codes. And, more recently, we have begun to participate more strongly in the experimental program being carried out on PBFA II. Our conclusions based on these studies are summarized here. 42 refs., 104 figs., 3 tabs.« less