Propagation and collisionless damping of topologically-protected surface plasma waves in non-uniformly magnetized plasma columns

Abstract Recent theoretical studies revealed the existence of topologically-protected surface plasma waves (TSPWs) in uniformly magnetized cold plasma columns. Reflections-free propagation of the TSPWs along arbitrarily-shaped plasma boundaries oriented perpendicularly to the magnetic field was shown to be preserved even when their collisionless damping by localized upper-hybrid resonances was accounted for. Here we extend this theory to the realistic case of three-dimensional magnetic field produced by finite-sized magnetic coils. We demonstrate that when TSPWs are launched in the direction of the decreasing magnetic field, they are collisionlessly absorbed within a highly localized (evanescent) region as they propagate away from the magnetic coil. We show that the resulting wave reflection can be negligible—in clear contrast with wave reflection from the corresponding evanescence regions of unmagnetized non-uniform plasmas.