Magnetic insulation of dielectric surfaces for the space environment

The influence of magnetic fields on dielectric surface breakdown is investigated for space conditions (presence of background plasma and gas, outgassing materials, and UV illumination), both for DC and pulsed electric and magnetic fields. DC conditions are susceptible to corona-type discharges with major influence of magnetic fields on discharge path and geometry. For pulsed voltages, insulation effects of the DC magnetic fields start at field amplitudes of 0.2 Tesla, dependent on the direction of the magnetic field with respect to the surface and the electric field. At 0.35 Tesla, an increase of breakdown voltage of more than 50% is observed (magnetic field parallel to the surface, material G-10 epoxy). Experimental results with DC field amplitudes of up to 0.8 Tesla are compared with the prediction of the saturated-surface-avalanche model for dielectric breakdown. In a second experimental setup, the insulating properties of pulsed magnetic fields produced by currents of up to 350 kA is studied, including conditions for magnetic self-insulation, vacuum gaps, and dielectric surface breakdowns.<>