Abstract

In the proposed theory for analyzing the electromagnetic radiation and electromagnetic mutual couplings in vacuum, the electromagnetic energy associated with a source is basically separated into two parts. One is the Coulomb-velocity energy that is attached to the source, the other is the radiative energy that will depart from the source. A macroscopic Schott energy term is introduced to account for the interchange between the Coulomb-velocity energy and the radiative energy. It has shown that the Schott energy will disappear with its sources but not simultaneously. It continues to exist for a short while after its source disappeared and will finally convert to radiative energy. The reactive electromagnetic energy consists of the Coulomb-velocity energy and the Schott energy, while the radiative energy also includes the contribution of the Schott energy. The theory provides a consistent formulation for the reactive energies and power balance equations both in time domain and frequency domain, which is validated with the radiation of a Hertzian dipole. By applying the Lienard-Wiechert potentials, this paper illustrates that the macroscopic Schott energy exactly agrees with the one obtained by many researchers for a non-relativistic moving charged particle.