Modes of Corona Discharges in Air

Corona discharges in air exist under several distinctive forms, either pulsative or stable. The properties of different corona modes are analyzed as they appear in a cylindrical distorted field. Differences between dc and ac excitations are emphasized. Corona discharges may produce energy loss without detectable radio noise or high noise at low energy loss, depending upon their form of appearance. The different withstands of asymmetric gaps under different polarities also find their explanation in corona mechanism.