Paraxial Gaussian wave beam propagation in an anisotropic inhomogeneous plasma

The beam tracing technique describes electromagnetic wave beam propagation in the short wavelength limit, including diffraction effects, not described by the usual geometric optics. It involves a set of ordinary differential equations: a central or reference ray is determined and around this the beam profile and the shape of the phase front are calculated. Here, these equations are obtained for a Gaussian wave beam. Analytic solutions in an inhomogeneous magnetized plasma are given for perpendicular propagation in a slab geometry. The beam is found to show a strong deformation of its cross section due to the anisotropy of the medium. The rotation of the cross section and that of the curvature of the phase front are discussed.