The effect of metal wires on vacuum flashover

Abstract

Surface flashover in vacuum is a kind of low-pressure plasma discharge, which seriously restricts the development of various areas, including pulsed-power devices, particle accelerators and other vacuum electronic devices. In this paper, the influence of silver wires on vacuum flashover is well studied with simulation and experiment. For getting the more accurate electric field, the finite element analysis software COMSOL is employed to simulate the surface electric field distribution with the presence of silver wires. It’s found that the silver wires increase the electric field at the metal-surface-vacuum junction and slightly decrease it at the cathode triple junction (CTJ). A particle-in-cell (PIC) simulation model is constructed to investigate the impact of silver wires on the flashover process. In order to estimate the influence of silver wires, three factors are analyzed, including the electrons distribution, average surface charge density and anode current. It can be observed that the metal wires suppress the surface charge accumulation and the development of multipactor, thus enhance the surface performance. The parameters of metal wires, for instance the width and number of wires, also make a difference. In the end, some experimental results are provided, which are consistent with the simulation results.