Propagation of a Gaussian beam in a nonhomogeneous plasma

The asymptotic theory of Choudhary and Felsen [IEEE Trans. Antennas Propag. AP‐21, 827 (1973)] on the propagation of scalar inhomogeneous waves in two‐dimensional isotropic media is extended to the case of three‐dimensional vector fields. The theory is applied to the propagation of Gaussian beams in nonhomogeneous media. The wave trajectory equations are then reformulated for anisotropic media and used for tracking a Gaussian beam in a tokamak plasma.