Time and frequency-resolved surface currents on insulators

The movement of charges deposited from a corona discharge on insulator surfaces was measured using sweeping potential difference V/sub s/ applied between electrodes placed on the surface. It is shown that surface charges are relatively highly mobile, provided their density Q/sub d/ is sufficiently high, and increase rapidly with Q/sub d/. The collected surface charge Q/sub s/ increases rapidly from very low values at low V/sub s/ and tends towards Q/sub d/, signifying complete removal. The lateral current i(t) as function of time after the application of V/sub s/ is nonexponential, tending to a t/sup -n/ dependence, where n<1. The flow of current becomes filamentary at sufficiently high Q/sub d/ and V/sub s/.<
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