Dispersion Characteristics of a Plasma Column in a Toroidal Waveguide

The dispersion characteristics of a toroidal waveguide in the presence of a plasma column are considered. The solution of the wave equation in a toroidal waveguide is presented using an analytical approximation method. In this method, the curvature of the axis of the waveguide is considered as a disturbance parameter to the straight circular cylinder approximation. The perturbed torus field for both the plasma and the vacuum regions is expanded in terms of the eigenfunctions of the unperturbed quantities. The effect of the plasma column in the toroidal waveguide is considered as the second perturbation factor in MHD equations. The perturbed Maxwell's equations along with the perturbed momentum transverse and the continuity equations lead to dispersion relation.