Modeling the Leakage of Hiss Waves From the Plasmasphere

Abstract Plasmaspheric hiss waves can cross the plasmasphere boundary layer (PBL) and leak into the plasmatrough, serving as the main source of exohiss waves. However, it remains unclear how the PBL and wave characteristics affect the leakage process of hiss waves. In this study, we conducted a detailed parametric ray tracing study to model the leakage of hiss waves to examine these effects. We find that the shrinking plasmasphere with a narrow PBL favors the leakage of hiss waves from the plasmasphere. Regardless of PBL characteristics, there exists an optimal region inside the plasmasphere where hiss waves are more likely to leak out. The leakage possibility of hiss waves decreases rapidly away from this optimal region, and the launching directions of the leaked hiss waves are opposite on either side of this optimal region. In addition, hiss waves with lower frequencies leak out of the plasmasphere more easily. Our results deepen the understanding of factors controlling the leakage of hiss waves from the plasmasphere and the subsequent formation of exohiss waves in the plasmatrough.