Quasi‐Optical Ray Tracing of Gaussian Beams in the Magnetosphere

Abstract A method for tracing rays in tokamak plasmas is applied to tracing rays in the Earth's magnetosphere. The problem of computing power flux from pencil rays using classical geometric optics that occurs when constituent rays exhibit coplanarity is addressed by appealing to complex geometric optics. The construction of Gaussian beams is discussed and the quasi‐optical method of tracing such beams is given. Examples of tracing Gaussian beams from a ground transmitter, a partial beam, and from a satellite location are presented. A median method for dealing with nonviable contributions to the power flux from sections of the beam encountering caustics or otherwise experiencing coplanarity is described. The effect of beam parameter choices on the resulting power flux computation is provided for each of the examples.