Discrete classical electromagnetism

RESUMO

The electric charges that make up charge distributions and currents in classical electromagnetism (EM) are point charge electrons with a fixed finite charge. This means that a truly continuous charge distribution or current cannot be formed because that would require infinitesimal charges. If the number of electrons in any distribution is very large, the distributions can be approximately continuous, and can be used in many applications, but the discrete character of the distributions has a major effect on other physical effects. We consider two of those effects in this paper. Does a point charge have infinite self-energy, and does a moving current loop have an electric dipole moment?