Shprits Y. Y., A. Y. Drozdov, M. Spasojevic, A. C. Kellerman, M. E. Usanova, M. J. Engebretson, O. V. Agapitov, I. S. Zhelavskaya, T. J. Raita, H. E. Spence, D. N. Baker, H. Zhu, N. A. Aseev, (2016), Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts, Nature Communications, 7, doi:10.1038/ncomms12883
Abstract
The dipole configuration of the Earth’s magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes.Authors (sorted by name)
Agapitov Aseev Baker Drozdov Engebretson Kellerman Raita Shprits Spasojevic Spence Usanova Zhelavskaya ZhuJournal / Conference
Nature CommunicationsAcknowledgments
This research was supported by the Helmholtz Association Recruiting Imitative programme, NASA grants NNX16AF91G,NNX13AE34G, NNX10AK99G, NNX15AI94G and NNX16AG78G, RBSP-ECT funding through JHU/APL contract 967399 under NASA contract NAS5-01072, JHU/APL contract 922613 (RBSP-EFW), NASA Grant NNX16AF85G, NSF GEM AGS-1203747 and UC Lab Fee grant 12-LR-235337, project PROGRESS funded by EU Horizon 2020 No 637302 and International Space Science Institute (Bern).Grants
12-LR-235337 637302 922613 967399 AGS-1203747 NAS5‐01072 NNX10AK99G NNX13AE34G NNX15AI94G NNX16AF85G NNX16AF91G NNX16AG78GBibtex
@article{10.1038/ncomms12883,
author = {Shprits, Yuri Y. and Drozdov, Alexander Y. and Spasojevic, Maria and Kellerman, Adam C. and Usanova, Maria E. and Engebretson, Mark J. and Agapitov, Oleksiy V. and Zhelavskaya, Irina S. and Raita, Tero J. and Spence, Harlan E. and Baker, Daniel N. and Zhu, Hui and Aseev, Nikita A.},
title = {Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts},
year = {2016},
journal = {Nature Communications},
volume = {7},
number = {12883},
doi = {10.1038/ncomms12883},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016JA022546},
eprint = {https://www.nature.com/articles/ncomms12883#supplementary-information},
abstract = {The dipole configuration of the Earth’s magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although significant advances have been made in understanding the acceleration mechanisms in the radiation belts, the loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout the belts on the energy spectrum and pitch angle (angle between the velocity of a particle and the magnetic field) distribution of electrons up to ultra-relativistic energies. Here we show that although relativistic electrons are enhanced, ultra-relativistic electrons become depleted and distributions of particles show very clear telltale signatures of electromagnetic ion cyclotron wave-induced loss. Comparisons between observations and modelling of the evolution of the electron flux and pitch angle show that electromagnetic ion cyclotron waves provide the dominant loss mechanism at ultra-relativistic energies and produce a profound dropout of the ultra-relativistic radiation belt fluxes.}
}