Plasmaspheric hiss is an important wave mode for the dynamics of inner terrestrial magnetosphere plasma populations. It acts to scatter high-energy electrons out of trapped orbits about Earth and into the atmosphere, defining the inner edge of the radiation belts over a range of energies. A low-frequency component of hiss was recently identified and is important for its ability to interact with higher-energy electrons compared to typically considered hiss frequencies. This study compares the statistical properties of low- and high-frequency plasmaspheric hiss in the terrestrial magnetosphere, demonstrating that they are statistically distinct wave populations. Low-frequency hiss shows different behavior in frequency space, different spatial localization (in magnetic local time and radial distance), and different amplitude distributions compared to high-frequency hiss. The observed statistical properties of low-frequency hiss are found to be consistent with recently developed theories for low-frequency hiss generation. The results presented here suggest that careful consideration of low-frequency hiss properties can be important for accurate inclusion of this wave population in predictive models of inner magnetosphere plasma dynamics.
Bibliographical noteFunding Information:
The authors thank the Van Allen Probes team, especially the EFW and EMFISIS teams for their support. This work was funded by NASA award NAS5-01072. All data used in this work are available from the EFW and EMFISIS team websites, which one can link to from here http://rbspgway.jhuapl.edu.
©2017. American Geophysical Union. All Rights Reserved.
- Van Allen Probes
- inner magnetosphere
- plasma waves
- plasmaspheric hiss
- wave statistics