Comparative analysis of two formulations of geometrical optics. The effective dielectric tensor

Two apparently diverse formulations of geometrical optics relevant to space - and time varying dispersive, anisotropic media are shown to be equivalent by virtue of the relationship between the effective dielectric tensor and the plane-wave dielectric tensor. As a counterpart of the wave kinetic equa tion governing the wave-action density in phase space, the equation for the transport of action density in physical configuration space is obtained, w hich entails, in particular, a wavepacket adiabatic invariant in the limit of which the effect of both dissipation and (internal and/or external) curr ent-sources is negligible.