Computation of ion-flow fields of AC coronating wires by charge simulation techniques

A method is developed for computing the ion flow from an AC coronating wire above the ground plane, without resort to unnecessary simplifying assumptions. The emission of ions is considered to take place from the wire when the surface field of the wire exceeds the onset value. The space charges are simulated by discrete line charges, and the charge simulation technique is used to compute the charge emission from the coronating wire during corona periods over both the positive and negative half cycles. The simulation line charges are displaced away from and back to the wire by the prevailing AC field with a subsequent recombination between the outgoing and returning line charges of opposite polarities. Among the parameters computed are the corona current components and their time variations during the positive and negative half cycles, the corona charge voltage characteristics, and the corona onset and ionization onset voltages as well as the corona ending voltage over the succeeding positive and negative half cycles. The computed corona power losses agreed reasonably with those measured experimentally