Equivalent image charges of a prolate spheroid under an external electric field

This paper presents the image charges for a prolate spheroid under an external electric field. The equivalent image charges can substitute the spheroid to represent the potential that the free or polarization charges, induced by the external field on the spheroid, contribute to the exterior. In order to generalize the image charges for an arbitrary external field, we apply cylindrical image charges along the interfocal line of the spheroid, and explain the determination of the charge distribution and the calculation of the potential from the images. Examples are included to demonstrate the applicability of the image charges in field calculation.