Statistical Study on Locally Generated High-Frequency Plasmaspheric Hiss and Its Effect on Suprathermal Electrons: Van Allen Probes Observation and Quasi-linear Simulation

The local generation of high-frequency plasmaspheric hiss has recently been reported by a case study (He et al., 2019, https://doi.org/10.1029/2018GL081578). In this research, we perform statistics of global distributions of the locally generated high-frequency plasmaspheric hiss (LHFPH) for different levels of substorm activity, using 6-year observational data from Van Allen Probes. The statistics find that the LHFPH amplitude presents a strong magnetic local time (MLT) asymmetry and highly depends on substorm activity, and intense LHFPHs occur from predawn to dusk side and can penetrate into inner plasmasphere of L ∼ 3 during AE > 300 nT. The statistical LHFPH spectrum shows that its frequency increases with the ambient magnetic field, with peaked wave powers between 0.1 and 0.5 fce. Based on the statistical properties of LHFPH, we evaluate the electron diffusion coefficients using quasi-linear theory. Those results suggest that electron pitch angle scattering driven by LHFPH could be a potential mechanism for the precipitation loss of suprathermal electrons of 0.1 keV to tens of keV, which can impact the ionization and chemical changes in the upper atmosphere.