Study on Negative Corona Discharge of the Small Spherical Metal Electrode

The negative corona discharge between a small spherical metal electrode (SSME) and a grounded plane electrode (GPE) was often a concern. The ring mode discharge and the dot mode discharge were found in the experimental study. Up until now, these two phenomena are not verified in simulation study. Simulation on the negative corona discharge between an SSME and a GPE is staged in this article. The pulse currents in negative corona discharge are analyzed under different voltages, radius of the SSME, and gap distance coupling fluid dynamic equations and Poisson equation based on the axisymmetric model. The interesting phenomenon found is that the corona discharges sequentially happen at different central angles on the surface of the SSME starting with the point nearest to the GPE. The negative corona discharges generated by the SSME and the hemispherical metal electrode are compared. The mechanism of discharge is analyzed by comparing their current pulses, electric field intensities, and changes in the concentration of ions. The ring mode discharge and the dot mode discharge are shown in our simulation. The reason for the formation of the ring mode discharge is also given.