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

摘要

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 similar to 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 f (ce). 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.