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Title: Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions

Abstract

Here, we present an analysis of “boomerang-shaped” pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on 7 June 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90° pitch angle electrons, the phase change of the flux modulations across energy exceeds 180° and increasingly tilts with time. Using estimates of the arrival time of particles of different pitch angles at the spacecraft location, a scenario is investigated in which shock-induced ULF waves interact with electrons through the drift resonance mechanism in a localized region westward of the spacecraft. Numerical calculations on particle energy gain with the modified ULF wavefield reproduce the observed boomerang stripes and modulations in the electron energy spectrogram. The study of boomerang stripes and their relationship to drift resonance taking place at a location different from the observation point adds new understanding of the processes controlling the dynamics of the outer radiation belt.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1];  [1]; ORCiD logo [1]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [5]
  1. Peking Univ., Beijing (China)
  2. Univ. of Alberta, Edmonton, AB (Canada)
  3. Univ. of New Hampshire, Durham, NH (United States)
  4. The Aerospace Corp., Los Angeles, CA (United States)
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
National Aeronautic and Space Administration (NASA); USDOE
OSTI Identifier:
1402655
Report Number(s):
LA-UR-17-28036
Journal ID: ISSN 0094-8276; TRN: US1702890
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 44; Journal Issue: 15; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; Heliospheric and Magnetospheric Physics; ULF waves; drift resonance; wave-particle interaction; radiation belts; localized waves; interplanetary shock

Citation Formats

Hao, Y. X., Zong, Q. -G., Zhou, X. -Z., Rankin, R., Chen, X. R., Liu, Y., Fu, S. Y., Spence, H. E., Blake, J. B., and Reeves, Geoffrey D.. Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions. United States: N. p., 2017. Web. doi:10.1002/2017GL074006.
Hao, Y. X., Zong, Q. -G., Zhou, X. -Z., Rankin, R., Chen, X. R., Liu, Y., Fu, S. Y., Spence, H. E., Blake, J. B., & Reeves, Geoffrey D.. Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions. United States. doi:10.1002/2017GL074006.
Hao, Y. X., Zong, Q. -G., Zhou, X. -Z., Rankin, R., Chen, X. R., Liu, Y., Fu, S. Y., Spence, H. E., Blake, J. B., and Reeves, Geoffrey D.. Mon . "Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions". United States. doi:10.1002/2017GL074006.
@article{osti_1402655,
title = {Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions},
author = {Hao, Y. X. and Zong, Q. -G. and Zhou, X. -Z. and Rankin, R. and Chen, X. R. and Liu, Y. and Fu, S. Y. and Spence, H. E. and Blake, J. B. and Reeves, Geoffrey D.},
abstractNote = {Here, we present an analysis of “boomerang-shaped” pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on 7 June 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90° pitch angle electrons, the phase change of the flux modulations across energy exceeds 180° and increasingly tilts with time. Using estimates of the arrival time of particles of different pitch angles at the spacecraft location, a scenario is investigated in which shock-induced ULF waves interact with electrons through the drift resonance mechanism in a localized region westward of the spacecraft. Numerical calculations on particle energy gain with the modified ULF wavefield reproduce the observed boomerang stripes and modulations in the electron energy spectrogram. The study of boomerang stripes and their relationship to drift resonance taking place at a location different from the observation point adds new understanding of the processes controlling the dynamics of the outer radiation belt.},
doi = {10.1002/2017GL074006},
journal = {Geophysical Research Letters},
number = 15,
volume = 44,
place = {United States},
year = {Mon Jul 10 00:00:00 EDT 2017},
month = {Mon Jul 10 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on July 10, 2018
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