Analysis of power flow in a plasma opening switch coupled to an electron-beam diode

Summary form only given. Analysis is performed on data obtained from the HAWK inductive storage generator at the Naval Research Laboratory using a Plasma Opening Switch (POS) to drive an electron-beam (e-beam) diode load. The aim of this analysis is to gain new insights into the POS opening process and its effect on switch-load coupling, a phenomenon which is not currently well understood. Currents and voltages measured both at the generator and at the load are used to infer load impedance, flow impedance, load power, POS gap size, and the critical POS gap for magnetic insulation. An important finding is that, at the time of peak load power, the inferred POS gap size is equal to the critical POS gap for magnetic insulation in both switch-limited and load-limited operation. This suggests that POS-load coupling is self-regulated to maintain saturated flow in the POS. Generator current and voltage upstream of the POS are used to determine the time varying inductance upstream of the POS current channel. From this inductance calculation, the location of the current channel at the time of switch opening may be inferred and compared with the location where bremsstrahlung emission is observed to begin in side-viewing X-ray pinhole photographs of HAWK. The effect of varying the conduction time, the anode-cathode gap and the POS-to-load distance on the inferred current-channel location at the time of POS opening is studied.