THE CONTROL OF CORONA CURRENT DISTRIBUTION USING SHAPED ELECTRODES

The mobility model for ionic flow in a corona discharge restricts the trajectories of ions to follow electric field lines. An axisymmetric a rrangement of electrodes consisting of a short wire supported by metal lic rods inside a grounded cylinder was used to produce ion emission a long a localized section of corona wire. By varying the geometry of th e support structure of the central corona electrode it was possible to vary the field configuration in the ionic region, and hence the coron a current density in the axial direction. The hybrid Finite Element-Me thod of Characteristics technique used to analyze the configuration co nfirmed the experimental results and shows that this ionic focusing ca n be used to concentrate the current onto a localized section of the o uter electrode. This may have useful applications in such areas as ele ctrostatic coating and surface treatment.