Influence of Solar Wind Dynamic Pressure on Hiss Waves: Based on Satellite Observations and Ray Tracing Simulations

Abstract In this study, we utilized over 5 years of data from the Van Allen Probes to investigate the impact of solar wind dynamic pressure ( P SW ) on the amplitude of plasmaspheric hiss. Observations reveal that lower‐frequency hiss (30–600 Hz) weakens under conditions of enhanced P SW , in contrast to the behavior of higher‐frequency hiss (600–2,500 Hz). The enhancement of local cyclotron resonance fails to account for the variations in lower‐frequency hiss, suggesting that hiss originating from chorus may be the key driver of this phenomenon. Ray tracing simulations were employed to investigate the influence of altered magnetic field configurations, Landau damping, and source region variations on the propagation of chorus waves into hiss waves. The simulation results reveal that the variation of magnetic field reconfiguration driven by enhanced P SW does not significantly alter the access of chorus waves into the plasmasphere. Variations in wave damping during chorus propagation constitute another critical factor, and there is no increased Landau damping in the process of chorus evolving into hiss under conditions of strong P SW . On the other hand, considering the different source regions for hiss of varying frequencies, the lower‐frequency hiss corresponds to a source region closer to the magnetopause. The compressed magnetopause may remove part of the source region for lower‐frequency hiss, leading to its weakening, as confirmed by ray tracing results. These results advance our understanding of whistler wave evolution and its P SW dependence.