Surface ARC Discharges on Spacecraft Dielectrics

Propagating arc discharges are the result of electrical breakdown in electron-beam-charged dielectrics. For incident electron accelerating voltages in the range of 1 to 30 kV, the charge accumulation is primarily within a few lim of the exposed surface, so that the propagating subsurface arc frequently bursts through the surface, ejecting ionized debris and an appreciable fraction of the accumulated electrons, This blowoff current has reached a peak value of 100 to > 1000A in the laboratory and thus, when it occurs on spacecraft materials, severe interference to control systems could be the result. Such interference on spacecraft has occured many times, correlating with magnetic storm conditions. The present state of understanding of this phenomenon will be reviewed in this paper.