Surface flashover of solid dielectric in vacuum

Abstract

The surface of a solid dielectric insulator becomes electrically charged when subjected to a high-voltage stress in vacuum. A method for calculating the surface flashover voltage based on the assumption that the discharge occurs in a layer of desorbed gases from the insulator surface is proposed. The electric field strength required to cause surface flashover is calculated by taking into account the secondary electron emission characteristics of the dielectric material. The dependence of the surface flashover field on the insulating material is deduced. A dependence of the flashover voltage on the insulator length to a power law of 0.5 is theoretically predicted. The calculated surface flashover voltage is compared with the previously reported measurements and good agreement is obtained.