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Quantifying the relative contributions of substorm injections and chorus waves to the rapid outward extension of electron radiation belt

Su Z., H. Zhu, F. Xiao, H. Zheng, Y. Wang, Q. -. Zong, Z. He, C. Shen, M. Zhang, S. Wang, C. A. Kletzing, W. S. Kurth, G. B. Hospodarsky, H. E. Spence, G. D. Reeves, H. O. Funsten, J. B. Blake, D. N. Baker, (2014), Quantifying the relative contributions of substorm injections and chorus waves to the rapid outward extension of electron radiation belt, J. of Geophys. Res. [Space Physics], 119, 10,023-10,040, doi:10.1002/2014JA020709

Abstract

AbstractWe study the rapid outward extension of the electron radiation belt on a timescale of several hours during three events observed by Radiation Belt Storm Probes and Time History of Events and Macroscale Interactions during Substorms satellites and particularly quantify the contributions of substorm injections and chorus waves to the electron flux enhancement near the outer boundary of radiation belt. A comprehensive analysis including both observations and simulations is performed for the first event on 26 May 2013. The outer boundary of electron radiation belt moved from L = 5.5 to L > 6.07 over about 6 h, with up to 4 orders of magnitude enhancement in the 30 keV to 5 MeV electron fluxes at L = 6. The observations show that the substorm injection can cause 100% and 20% of the total subrelativistic (∼0.1 MeV) and relativistic (2–5 MeV) electron flux enhancements within a few minutes. The data-driven simulation supports that the strong chorus waves can yield 60%–80% of the total energetic (0.2–5.0 MeV) electron flux enhancement within about 6 h. Some simple analyses are further given for the other two events on 2 and 29 June 2013, in which the contributions of substorm injections and chorus waves are shown to be qualitatively comparable to those for the first event. These results clearly illustrate the respective importance of substorm injections and chorus waves for the evolution of radiation belt electrons at different energies on a relatively short timescale.

Authors (sorted by name)

Baker Blake Funsten He Hospodarsky Kletzing Kurth Reeves Shen Spence Su Xiao Zhang Zheng Zhou Zong Zhu

Journal / Conference

Journal Of Geophysical Research (Space Physics)

Acknowledgments

The interplanetary parameters, geomagnetic indices, and THEMIS data are obtained at the CDAWeb (http://cdaweb.gsfc.nasa.gov/cdaweb/istp_public/). The RBSP data are available at the websites (http://emfisis.physics.uiowa.edu/Flight/ for EMFISIS and http://www.rbsp-ect.lanl.gov/data_pub/ for ECT). We acknowledge J.H. King, N. Papatashvilli, and CDAWeb for the use of interplanetary parameters and magnetospheric indices and acknowledge V. Angelopoulos, J.W. Bonnell, F.S. Mozer, A. Roux, R.E. Ergun, U. Auster, K.H. Glassmeier, W. Baumjohann, and SSCWeb for the use of THEMIS data. This work was supported by the National Natural Science Foundation of China grants 41274169, 41274174, 41174125, 41131065, 41121003, 41074120, 41231066, and 41304134, the Chinese Academy of Sciences grants KZCX2‐EW‐QN510 and KZZD‐EW‐01‐4, the National Key Basic Research Special Foundation of China grant 2011CB811403, the Strategic Priority Research Program on Space Science of the Chinese Academy of Sciences grant XDA04060201, and the Fundamental Research Funds for the Central Universities WK2080000031. This work was also supported from JHU/APL contracts 921647 and 967399 under NASA Prime contract NAS5‐01072.

Grants

921647 967399 NAS5‐01072

Bibtex

@article{doi:10.1002/2014JA020709,
author = {Su, Zhenpeng and Zhu, Hui and Xiao, Fuliang and Zheng, Huinan and Wang, Yuming and Zong, Q.-G. and He, Zhaoguo and Shen, Chao and Zhang, Min and Wang, Shui and Kletzing, C. A. and Kurth, W. S. and Hospodarsky, G. B. and Spence, H. E. and Reeves, G. D. and Funsten, H. O. and Blake, J. B. and Baker, D. N.},
title = {Quantifying the relative contributions of substorm injections and chorus waves to the rapid outward extension of electron radiation belt},
journal = {Journal of Geophysical Research: Space Physics},
volume = {119},
number = {12},
pages = {10,023-10,040},
year ={2014},
keywords = {radiation belt, electron acceleration, wave-particle interaction, substorm injection, chorus wave, Van Allen Probes},
doi = {10.1002/2014JA020709},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2014JA020709},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2014JA020709},
abstract = {AbstractWe study the rapid outward extension of the electron radiation belt on a timescale of several hours during three events observed by Radiation Belt Storm Probes and Time History of Events and Macroscale Interactions during Substorms satellites and particularly quantify the contributions of substorm injections and chorus waves to the electron flux enhancement near the outer boundary of radiation belt. A comprehensive analysis including both observations and simulations is performed for the first event on 26 May 2013. The outer boundary of electron radiation belt moved from L = 5.5 to L > 6.07 over about 6 h, with up to 4 orders of magnitude enhancement in the 30 keV to 5 MeV electron fluxes at L = 6. The observations show that the substorm injection can cause 100% and 20% of the total subrelativistic (∼0.1 MeV) and relativistic (2–5 MeV) electron flux enhancements within a few minutes. The data-driven simulation supports that the strong chorus waves can yield 60%–80% of the total energetic (0.2–5.0 MeV) electron flux enhancement within about 6 h. Some simple analyses are further given for the other two events on 2 and 29 June 2013, in which the contributions of substorm injections and chorus waves are shown to be qualitatively comparable to those for the first event. These results clearly illustrate the respective importance of substorm injections and chorus waves for the evolution of radiation belt electrons at different energies on a relatively short timescale.}
}