Effect of toroidal magnetic field variations on the spectra of azimuthal surface waves in metal waveguides entirely filled with plasma

The propagation of surface waves transverse to the circular axis of a toroidal magnetized metal waveguide entirely filled with a plasma is studied using perturbation theory. The distribution of the fields of these waves in such a waveguide structure is investigated. It is shown that the toroidicity introduces a second-order correction to the eigenfrequency of the surface waves.