Topologically-protected surface plasma waves in magnetized multi-species plasmas*

The topological properties of a magnetized cold gaseous plasma have recently been explored and the existence of topologically protected edge states have been established [1,2,3,4]. It has been shown that both high-frequency (electrons-dominated) [1,2,3] and low-frequency (ion-dominated) [4] topological surface plasma waves (TSPWs) exist at the interface of a bounded multi-species magnetized plasma. We demonstrate that if a continuum of localized plasma resonances exists inside the smooth plasma density ramp separating plasmas with different topological Chern indices, TSPWs undergo collisionless damping due to coupling with upper- and lower-hybrid resonances. Here we present a semi-analytical model yielding dispersion relations of TSPWs within the entire bulk plasma propagation bandgap for arbitrary density ramps. We also demonstrate by ab-initio 3D particle-in-cell simulations that edge states, undergoing collisionless damping, are robust, unidirectional, and topologically protected. These finding broadens the possible applications of these exotic excitations in space and laboratory plasmas.

 

[1] J. Parker et al, Phys. Rev. Lett. 124, 195001 (2020).

[2] Yichen Fu and Hong Qin, Nature Communications 12, 3924 (2021).

[3] Roopendra S Rajawat, V. Khudik, and G. Shvets, arXiv:2203.06693v1(2022)

[4] Roopendra S Rajawat, T. Wang and G. Shvets, arXiv:2209.12748v1(2022)