The field near the sample Foil in the corona system with a grid

In this paper, the field distribution of a point-to-plane corona discharge is demonstrated. As a grid mesh is inserted between the needle and the plane, the electric field near the sample foil tends towards uniformity. This conclusion is supported by measuring isopotential surfaces of the alternating current field, which simulates the corona field. We also measure the surface-potential distribution of the foil charged by corona with grid. This experimental results shows that the field near the foil is virtually uniform.