Leaky modes guided along cylindrical plasma channels with enhanced density

Abstract

Summary form only given. Magnetic-field-aligned cylindrical enhancements of plasma density can arise near antennas in magnetized plasma due to ionization or thermal-diffusion nonlinear effects. Such artificial plasma channels can be used for improving the antenna coupling to whistler-mode waves propagating below the electron gyrofrequency. The paper investigates the excitation and propagation of leaky modes guided by cylindrical enhancements in the whistler frequency range. This problem is important because in many practical cases, only the contribution of leaky, modes have to be taken into account when analyzing the field pattern in the channel at moderately distant points from the source. We consider the excitation of leaky modes by a given time-harmonic ring electric current with its axis oriented both parallel and perpendicular to an external static magnetic field. The theoretical consideration of the propagation of leaky modes were performed using the rigorous full-wave solution for the source-excited field.