Influence of Insulator Barrier on Surface Flashover Development in Vacuum

This paper deals with the surface flashover phenomena on insulator surface in vacuum. Vacuum surface flashover can occur with processes of field electron emission from cathode and subsequent secondary electron emission avalanche (SEEA). To suppress the SEEA development in flashover process, one possible method to install a barrier on insulator surface was investigated. The electrode configuration with a rod-electrode, a plane-insulator with a back electrode and an edge electrode to one side was constructed. The voltage and current waveforms, as well as a probe current waveform for estimating a transiently formed surface charge, during impulse voltage application were measured. As a result, by installing barrier, although the progress and spread of the SEEA could temporarily be suppressed, secondary electrons crossed over the barrier due to electric field distortion by overcharge formed in the barrier.