Magnetic insulation of dielectric surfaces in vacuum using DC magnetic fields

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Title: Magnetic insulation of dielectric surfaces in vacuum using DC magnetic fields
Author: Korzekwa, Richard A
Abstract: The influence of dc magnetic fields on dielectric surface breakdown in vacuum using pulsed test voltages is investigated . Predictions from the "saturated surface avalanche" breakdown model and the experimental results show -magnetic insulation effects , i .e . , an increase in flashover voltage , at magnetic field amplitudes as low as 0 .1 T . The magnetic field is oriented parallel to the insulator surface and perpendicular to the electric field . An increase in flashover voltage is seen for the magnetic field direction where the ExB drift is away from the surface , while a decrease followed by an increase in flashover voltage is seen for ExB drift into surface . The magnitude of the insulation effect depends on the dielectric material , ambient pressure , surface roughness , and presence of background plasma . In order to achieve magnetic insulation with and without a background plasma , it is sufficient to apply the magnetic field in the cathode region only . Magnetic insulation has also been observed using small low weight permanent magnets which can be used to increase the flashover voltage in a low density plasma environment where the electron density is on the order of W cm -3 . The dependence of the flashover voltage on the square root of the gap distance is retained with the application of an insulating magnetic field . Also , prebreakdown luminance measurements support the "saturated surface avalanche" model .
URI: http : / /hdl .handle .net /2346 /22636
Date: 1990-05

Citation

Magnetic insulation of dielectric surfaces in vacuum using DC magnetic fields. Doctoral dissertation, Texas Tech University. Available electronically from http : / /hdl .handle .net /2346 /22636 .

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