Usanova M. E., A. Drozdov, K. Orlova, I. R. Mann, Y. Shprits, M. T. Robertson, D. L. Turner, D. K. Milling, A. Kale, D. N. Baker, S. A. Thaller, G. D. Reeves, H. E. Spence, C. Kletzing, J. Wygant, (2014), Effect of EMIC waves on relativistic and ultrarelativistic electron populations: Ground-based and Van Allen Probes observations, Geophysical Research Letters, 41, 1375-1381, doi:10.1002/2013GL059024
Abstract
AbstractWe study the effect of electromagnetic ion cyclotron (EMIC) waves on the loss and pitch angle scattering of relativistic and ultrarelativistic electrons during the recovery phase of a moderate geomagnetic storm on 11 October 2012. The EMIC wave activity was observed in situ on the Van Allen Probes and conjugately on the ground across the Canadian Array for Real-time Investigations of Magnetic Activity throughout an extended 18 h interval. However, neither enhanced precipitation of >0.7 MeV electrons nor reductions in Van Allen Probe 90° pitch angle ultrarelativistic electron flux were observed. Computed radiation belt electron pitch angle diffusion rates demonstrate that rapid pitch angle diffusion is confined to low pitch angles and cannot reach 90°. For the first time, from both observational and modeling perspectives, we show evidence of EMIC waves triggering ultrarelativistic (~2–8 MeV) electron loss but which is confined to pitch angles below around 45° and not affecting the core distribution.Authors (sorted by name)
Baker Drozdov Kletzing Orlova Reeves Shprits Spence Thaller Turner Usanova WygantJournal / Conference
Geophysical Research LettersAcknowledgments
We wish to thank the Van Allen Probe ECT, EFW, and EMFISIS instrument teams for data. This work is supported in part by the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization) consortium. MEU is partly supported by the Canadian Space Agency. IRM is supported by a Discovery Grant from Canadian NSERC. DLT is thankful for funding from NASA (THEMIS contract NAS5‐02099 and grant NNX12AJ55G) and the MAARBLE project. The research of K.O. was supported by the NASA Living with a Star Jack Eddy Postdoctoral Fellowship Program, administered by the University Corporation for Atmospheric Research.Grants
NAS5‐02099 NNX12AJ55GBibtex
@article{doi:10.1002/2013GL059024,
author = {Usanova, M. E. and Drozdov, A. and Orlova, K. and Mann, I. R. and Shprits, Y. and Robertson, M. T. and Turner, D. L. and Milling, D. K. and Kale, A. and Baker, D. N. and Thaller, S. A. and Reeves, G. D. and Spence, H. E. and Kletzing, C. and Wygant, J.},
title = {Effect of EMIC waves on relativistic and ultrarelativistic electron populations: Ground-based and Van Allen Probes observations},
year = {2014},
journal = {Geophysical Research Letters},
volume = {41},
number = {5},
pages = {1375-1381},
keywords = {EMIC waves, relativistic electrons, ultra-relativistic electrons, Van Allen Probes, pitch-angle diffusion, loss},
doi = {10.1002/2013GL059024},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2013GL059024},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2013GL059024},
abstract = {AbstractWe study the effect of electromagnetic ion cyclotron (EMIC) waves on the loss and pitch angle scattering of relativistic and ultrarelativistic electrons during the recovery phase of a moderate geomagnetic storm on 11 October 2012. The EMIC wave activity was observed in situ on the Van Allen Probes and conjugately on the ground across the Canadian Array for Real-time Investigations of Magnetic Activity throughout an extended 18 h interval. However, neither enhanced precipitation of >0.7 MeV electrons nor reductions in Van Allen Probe 90° pitch angle ultrarelativistic electron flux were observed. Computed radiation belt electron pitch angle diffusion rates demonstrate that rapid pitch angle diffusion is confined to low pitch angles and cannot reach 90°. For the first time, from both observational and modeling perspectives, we show evidence of EMIC waves triggering ultrarelativistic (~2–8 MeV) electron loss but which is confined to pitch angles below around 45° and not affecting the core distribution.}
}