DECADE Quad monolithic POS development on ACE 4 [pulsed power plasma opening switch

Abstract

The DECADE Quad (DQ) is a Defense Threat Reduction Agency's radiation effects simulator consisting of four individual DECADE Modules (DMs). When operated as a large area Bremsstrahlung source, each of the DMs utilize separate plasma opening switches (POSs) and e-beam loads. A monolithic POS for DQ is being developed for small area Bremsstrahlung source applications requiring a single e-beam diode. Power flow from the four DMs will be converged upstream of the monolithic POS which will drive a nominal 0.2 /spl Omega/, small area Bremsstrahlung source. The baseline approach for the development of a monolithic switch for DQ is a POS currently being tested on ACE 4. The applicability of ACE 4 as a test bed is based on a conduction current time(I/sub c/*T/sub c/) scaling argument applied to the conduction phase. The key concept for I/sub c/*T/sub c/ scaling, the preservation of the opening phase initial conditions, has both experiment and theoretical support. The DQ prototype coaxial POS uses a 9 cm radius cathode, a 3 cm A-K gap, and has a nominal 20 cm length. A set of 15 Teflon(R) substrate flashboards supply the necessary POS plasma, injected through a 60% transparent anode mesh. Issues being addressed in this development besides I/sub c/*T/sub c/ scaling include an understanding of current losses due to ion currents in the POS region and PQS-to-load coupling issues related to POS opening and plasma transport into the load region. In this paper, the authors report on the characterization of several POS-to-load coupling geometries on ACE 4.