Influence of the solid dielectric surface structure on the electric field at an air-barrier boundary

The distribution of electric field in air near a solid dielectric plate has been calculated using a model that takes into account the degree of roughness of the dielectric surface. Calculations performed for pyroceram show that the electric field strength at the vertices of juts on the dielectric surface can be 2.5–3.5 times (depending on the degree of surface roughness) greater than the values in the air gap. At the same time, the field strength in hollows is about ten times weaker than that at the juts. The obtained results agree with experimentally observed [1] changes in the intensity of discharge processes at a dielectric surface with increasing degree of roughness.