The Global Propagation of Hiss Waves Originating From Dynamic Plasmaspheric Plume

Abstract Hiss waves play a critical role in shaping Earth's radiation belts and mediating magnetosphere‐ionosphere energy transfer. Intense hiss emissions are frequently generated within dynamic plasmaspheric plumes through linear and nonlinear wave‐particle interactions. However, the contribution of plume hiss to the spatial distribution of hiss throughout the plasmasphere is not yet well quantified. In this study, we perform ray‐tracing simulations to investigate the global propagation of plume hiss under varying plume morphologies, including different widths and levels of density lumpiness. We find that most hiss power is confined near the local time sector of the plume. Narrower plumes with embedded density ducts significantly enhance earthward wave guidance into the plasmaspheric core, compared to wide, smooth plumes. Furthermore, a subset of rays guided azimuthally along the plasmapause can serve as seed waves for intense dayside hiss. Our results highlight the role of plume hiss in shaping the global‐scale distribution of hiss waves.