Plasma Cathode for a Short-Pulse Dielectric Wall Accelerator

Abstract

The Beam Research Program at Lawrence Livermore National Laboratory is continuing development of the dielectric wall accelerator (DWA), a type of accelerator which uses stacked pulse-forming lines (PFLs) to apply an accelerating field directly to the beam through a nonconducting vacuum boundary. Here, we report operation of a DWA as an electron diode using a surface flashover plasma cathode. Peak perveances in excess of 6 × 10 −6 A/V 3/2 were measured, with current extraction and pulse train format depending on flashover source timing and PFL switching speed.

Measurements of an expanding surface flashover plasma

“…This can be partially addressed by altering the shape of the electrodes to minimize the degree to which the discharge properties and location varied from shot to shot, as was done in Ref. 9. This shot to shot variation was particularly problematic for the biased-probe measurements.…”