A Multi-Satellite Statistical Analysis and Empirical Model of Plasmaspheric Hiss Based on Van Allen Probes and Arase Observations

Plasmaspheric hiss is a whistler-mode emission in the Earth’s plasmasphere and is a major contributor to the pitch-angle scattering and loss of radiation belt electrons. Previous statistical studies based on single-satellite observations have limited a systematic understanding of plasmaspheric hiss waves. In this study, we present a statistical analysis of plasmaspheric hiss using combined observations from the Van Allen Probes and the Arase spacecraft during 2012-2024. The use of two missions improves spatial coverage and enables a more comprehensive characterization of the hiss intensity distribution within magnetic latitudes up to 45°. The results show that hiss intensity is enhanced on the dayside and peaks at L ≈ 3-4. Based on these results, we develop an empirical regression model that parameterizes the dependence of the root-mean-square hiss magnetic field intensity on L-shell, magnetic local time (MLT) and magnetic latitude (MLAT). The influence of geomagnetic activity is further parameterized using polynomial fits to the Kp index. The model is applicable for L ≤ 6.5, Kp ≤ 6, all MLTs, and MLAT up to 45°, providing a practical representation of plasmaspheric hiss for radiation belt modeling applications.