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 kilovolts to tens of kilovolts, the charge accumulation is primarily within a few micrometers 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 can reach a peak value of hundreds or even thousands of amperes and thus, when it occurs on spacecraft materials, severe interference to control systems can be the result. The present state of understanding of this phenomenon will be reviewed.