ELECTROMAGNETISM OF ISOTROPIC RELATIVISTIC PLASMAS - MAXWELLS FORMALISM AND THE CHOICE OF GAUGE

We define a new generalized symmetrical permittivity tenser of rank tw o, chi(alpha beta), in order to characterize the inductions in Maxwell 's formalism for an isotropic relativistic plasma. We then show that o nly the Lorentz gauge allows one to write the field potentials with a propagator inversely proportional to this tenser. In this sense, we ma y say that the Lorentz gauge is the only one suitable for Maxwell's fo rmalism.