Statistical investigation of the frequency dependence of the chorus source mechanism of plasmaspheric hiss

We use data from eight satellites to statistically examine the role of chorus as a potential source of plasmaspheric hiss. We find that the strong equatorial (|λm| < 6°) chorus wave power in the frequency range 50 < f < 200 Hz does not extend to high latitudes in any MLT sector and is unlikely to be the source of the low frequency plasmaspheric hiss in this frequency range. In contrast, strong equatorial chorus wave power in the medium frequency range 200 < f < 2000 Hz is observed to extend to high latitudes and low altitudes in the pre-noon sector, consistent with ray tracing modelling from a chorus source and supporting the chorus to hiss generation mechanism. At higher frequencies, chorus may contribute to the weak plasmaspheric hiss seen on the dayside in the frequency range 2000 < f < 3000 Hz band, but is not responsible for the weak plasmaspheric hiss on the night-side in the frequency range 3000 < f < 4000 Hz. The research leading to these results has received funding from the Natural Environment Research Council (NERC) Highlight Topic grant NE/P01738X/1 (Rad-Sat) and the NERC grants NE/V00249X/1 (Sat-Risk) and NE/R016038/1. Jacob Bortnik received funding from NASA grant NNX14AI18G, and RBSP-ECT and EMFISIS funding provided by JHU/APL contracts 967399 and 921647 under NASA's prime contract NAS5-01072. Wen Li and Xiao-Chen Shen received funding from NASA grants 80NSSC20K0698 and 80NSSC19K0845, NSF grant AGS-1847818, and the Alfred P. Sloan Research Fellowship FG-2018-10936.