Electric Field of a Charge Moving in a Medium

Abstract

The object of this paper is purely pedagogic—to clear up an apparent difficulty in applying Gauss' theorem to the classical electric field associated with a charge moving in an infinite homogeneous nondispersive medium with a constant velocity exceeding the velocity of propagation of light in the medium (conditions under which Cherenkov radiation is emitted). This is done by investigating the behavior of the electric field intensity not only inside the cone defining the region that can be reached by light signals from the charge but also on the cone.