DIELECTRIC SURFACE FLASHOVER IN A SIMULATED LOW-EARTH-ORBIT ENVIRONMENT

Surface flashover on insulators under UV irradiation or with a plasma background was investigated with high-speed electrical and optical sen sors in order to clarify differences in the breakdown development comp ared to the pure vacuum case, Results with a plasma background show a more rapid development in the breakdown initiation compared to measure ments in vacuum with no plasma, With a magnetic shielding technique us ing permanent magnets, the duration of an applied voltage pulse can be increased by a factor of 2-3 without causing flashover. UV illuminati on on the electrodes decreases the flashover voltage (for the de case) or the voltage pulse duration without breakdown (for the pulsed case) , whereas UV illumination on the dielectric surface increases the flas hover potential.