Surface discharges on natural dielectrics in the solar system

In a variety of environments, notably those defined by the magnetospheres of the giant planets, natural dielectrics are exposed to large fluxes of charged particles. Laboratory simulations of these potentially discharge-inducing charging phenomena have been conducted to ascertain whether discharges can occur on natural dielectrics. Charging beam intensities ranged from 10 to the 10th to 10 to the 12th particles/sq cm per sec, with exposure times of 1-10 min; the lowest intensity is comparable to that expected on the surface of Io. Discharges were recorded during all exposures.