Wigner dynamics and limit of geometrical optics in inhomogeneous dispersive media

e study the limit of geometrical optics in dispersive inhomoge neous media. The short wavelength regime of the wave equation is investigated in the framework of the Wigner quasi-distribution function in the phase-space. The evolution of the field is expressed by a Cauchy problem for the position and direction of the optical rays. The extended time-frequency phase-space formalism furnishes a natural framework to study the fast oscillating limit of fields governed by non local in time pseudo-differential equations.