Continuum damping of topologically-protected edge modes at the boundary of a magnetized plasma

TL;DR

This paper investigates how topologically-protected surface plasma waves in magnetized plasmas experience collisionless damping via continuum coupling, yet retain their robustness and unidirectionality, with novel boundary interactions.

Contribution

It reveals the damping mechanism of topologically-protected plasma waves above the electron cyclotron frequency and explores their behavior at boundaries between damped and undamped regions.

Findings

Damped TSPWs exhibit collisionless damping through continuum coupling.

Damped TSPWs maintain unidirectionality and robustness.

Refraction occurs at boundaries between damped and undamped TSPWs without reflection.

Abstract

Recent extension of the topological ideas to continuous systems with broken time-reversal symmetry, such as magnetized plasmas, provides new insights into the nature of scattering-free topologically-protected surface plasma waves (TSPWs). We demonstrate a unique characteristic of TSPWs propagating above the electron cyclotron frequency: their collisionless damping via coupling to the continuum of resonant modes localized inside a smooth plasma-vacuum interface. Damped TSPWs retain their unidirectional nature and robustness against backscattering. When sheared magnetic field creates a boundary between damped and undamped TSPWs, the two refract into each other without reflections