Coaxial vacuum gap breakdown for pulsed power liners

Abstract

Recent work conducted at UC San Diego utilizes a high voltage system, up to 25kV, to study and analyze the vacuum breakdown mechanisms of a coaxial gap. An analysis of the coaxial gap has utilized laser interferometry for density profile, as well as magnetic field measurements via B-dot probes. Results show that breakdown is random about the azimuth, and that density of breakdown plasma is low (∼ne dl <5E16 cm2). The largest magnetic field strength is measured on the probe(s) closest to where breakdown occurs making it possible to triangulate the relative position breakdown occurred without the need for line of sight along the axis. Furthermore, diagnostic results coupled with the unpolished electrodes being at room temperature suggests that field emission is the dominant mechanism causing initial breakdown.