Pulsed magnetic field effects on dielectric surface flashover in vacuum

Date

1990-08

Journal Title

Journal ISSN

Volume Title

Publisher

Texas Tech University

Abstract

The influence of pulsed magnetic fields on dielectric surface flashover in vacuum is investigated under non-uniform field conditions. The magnetic field is applied parallel to the dielectric surface and perpendicular to the electric field, which is derived from a pulsed test voltage. Predictions from computer simulations of the saturated surface avalanche process, using non-uniform fields, point to the importance of conditions at the cathode in producing magnetic insulation effects, i.e., an increase in the surface flashover voltage with an applied magnetic field. Experimentally, substantial increases in the surface flashover voltage are observed with the vector ExB pointing away from the surface. The maximum relative increase in the surface flashover voltage occurs with the maximum magnetic field or the minimum electric field applied at the cathode. Breakdown over long paths, induced by the magnetic field when ExB points into the surface, is investigated experimentally. Experiments conducted with a low density background plasma indicate that the magnetic field successfully shields the insulator surface from the plasma electrons when ExB points away from the insulator surface.

Description

Keywords

Dielectrics, Pulse circuits, Electric displacement, Electromagnetic surface waves

Citation