The effect of neutrals on the performance of plasma opening switches

Summary form only given. We address the question of the limitations on voltage and current transfer to loads in magnetic storage systems utilizing microsecond conduction time plasma opening switches. We propose that the limitation of performance results from neutral atoms that are not entrained into the ionized material that is driven by the magnetic field of the rising generator current. Evidence in support of this proposition is gathered from experiments performed on the Ace-4 and Hawk generators. We set forth a theory to describe the effect of neutrals on the electrical performance of plasma opening switches. The neutral gas in assumed to be present in the region between the moving plasma mass and the generator, primarily in the region in which the plasma is injected initially. The essential elements of the theory are a weak photoionization source to seed the gas with a low concentration of electrons, and joule heating accompanied by further ionization and breakdown of the gas as voltage develops across the switch.