Field intensification at the contact point between a conducting plane and a spheroid or an elliptic cylinder

This paper presents an analysis of the electric field at the contact point of zero contact angle for different curvature of the dielectric interface near the contact point. The arrangement considered here is a dielectric solid (a spheroid or an elliptic cylinder) standing on a grounded plane under a uniform external field. The electric field has been calculated by using the boundary element method for 2D and AS arrangements. The calculation results show that the contact-point electric field is intensified by either decreasing the aspect ratio a/b of the dielectric solid or increasing the ratio of the material constant of the solid to that of the surrounding medium. Two simple equations are given for estimating the contact-point electric field for a range of the material-constant ratio with the errors less than 6.6%.