Simulation of the seat form of a negative corona discharge in a point-plane electrode system

A negative corona discharge in a point-plane electrode system is simulated. Equations for the transfer of electrons and ions are given as a drift-diffusion approximation. A mushroom-shaped corona seat is developed both in the model and experiment. There is determined the mechanism of this process: near the needle point within the corona sheath area, the charge structure is bipolar and causes the constriction of the field force lines, as well as the appearance of a narrow peak of intensity on the active electrode surface. On the contrary, in the space between the active and passive electrodes, there dominates a unipolar charge of negative ions, which is responsible for the repulsion of the field lines. The distortion of these lines leads to the formation of the mushroom glow of the corona discharge.