P. Degottal et J. Gariel, ELECTROMAGNETISM OF ISOTROPIC RELATIVISTIC PLASMAS - MAXWELLS FORMALISM AND THE CHOICE OF GAUGE, Journal of Plasma Physics, 52, 1994, pp. 431-442
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.