Electric field analysis of A-B-A insulation structure in vacuum

An A-B-A insulation structure is proposed to improve the characteristics of surface flashover in vacuum by adjusting the conductivity and permittivity of layer A. According to the electric field theory of series dielectrics, the DC and pulsed field distributions of the structure are calculated and the influences of the conductivity and permittivity of layer A on the electric fields of the vacuum-insulator-cathode triple junction and the vacuum-layer A-layer B triple junction are analyzed. It is found that this structure can effectively reduce, the electric field at the former junction while keep that at the later not too intense. The impact of layer A with different surface charges on the electric field of the two junctions is also analyzed. At last, the variation tendency of surface flash