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Evaluation of whistler mode chorus amplification during an injection event observed on CRRES

Li W., R. M. Thorne, N. P. Meredith, R. B. Horne, J. Bortnik, Y. Y. Shprits, B. Ni, (2008), Evaluation of whistler mode chorus amplification during an injection event observed on CRRES, J. Geophys. Res. [Space Physics], 113, doi:10.1029/2008JA013129

Abstract

The excitation of nightside whistler mode chorus emissions in the low-density region outside the plasmapause is investigated during an injection of plasma sheet electrons into the inner magnetosphere. CRRES data of the electron phase space density (PSD) over the LEPA energy range between 0.1 keV and 30 keV are used to develop an analytical model for the distribution function of injected low-energy electrons. The path-integrated growth of chorus waves is then evaluated with the HOTRAY code by tracing unducted whistler mode chorus waves in a hot magnetized plasma. The results indicate that newly injected electrons are responsible for the intensification of lower-band whistler mode chorus. However, slightly higher electron anisotropy than that obtained from the 5 min-averaged electron PSD data is required to reproduce the observed wave intensity during an injection event. We suggest that the injected electron anisotropy is reduced due to pitch angle scattering by the enhanced chorus waves within the 5-min interval over which the CRRES data are analyzed.

Authors (sorted by name)

Bortnik Horne Li Meredith Ni Shprits Thorne

Journal / Conference

Journal Of Geophysical Research (Space Physics)

Acknowledgments

This research was funded by the NSF grant ATM_0402615 and NASA Heliophysics Theory Program grant NNX08A035G.

Grants

ATM-0402615 NNX08A035G

Bibtex

@article{doi:10.1029/2008JA013129,
author = {Li, W. and Thorne, R. M. and Meredith, N. P. and Horne, R. B. and Bortnik, J. and Shprits, Y. Y. and Ni, B.},
title = {Evaluation of whistler mode chorus amplification during an injection event observed on CRRES},
journal = {Journal of Geophysical Research: Space Physics},
volume = {113},
year = {2008},
number = {A9},
pages = {},
keywords = {linear phase of chorus amplification},
doi = {10.1029/2008JA013129},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008JA013129},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2008JA013129},
abstract = {The excitation of nightside whistler mode chorus emissions in the low-density region outside the plasmapause is investigated during an injection of plasma sheet electrons into the inner magnetosphere. CRRES data of the electron phase space density (PSD) over the LEPA energy range between 0.1 keV and 30 keV are used to develop an analytical model for the distribution function of injected low-energy electrons. The path-integrated growth of chorus waves is then evaluated with the HOTRAY code by tracing unducted whistler mode chorus waves in a hot magnetized plasma. The results indicate that newly injected electrons are responsible for the intensification of lower-band whistler mode chorus. However, slightly higher electron anisotropy than that obtained from the 5 min-averaged electron PSD data is required to reproduce the observed wave intensity during an injection event. We suggest that the injected electron anisotropy is reduced due to pitch angle scattering by the enhanced chorus waves within the 5-min interval over which the CRRES data are analyzed.}
}