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Title: What Causes Radiation Belt Enhancements: A Survey of the Van Allen Probes Era

Abstract

We survey radiation belt enhancement events during the Van Allen Probes era to determine what mechanism is the dominant cause of enhancements and where it is most effective. Two primary mechanisms have been proposed: (1) betatron/Fermi acceleration due to the Earthward radial transport of electrons, which produces monotonic gradients in phase space density (PSD), and (2) “local acceleration” due to gyro/Landau resonant interaction with electromagnetic waves, which produces radially localized growing peaks in PSD. Here, to differentiate between these processes, we examine radial profiles of PSD in adiabatic coordinates using data from the Van Allen Probes and Time History of Events and Macroscale Interactions during Substorms satellites for 80 outer belt enhancement events from October 2012 to April 2017. Here, this study shows that local acceleration is the dominant acceleration mechanism for MeV electrons in the outer belt, with 87% of the enhancement events exhibiting growing peaks. The strong correlation of the location of these with geomagnetic activity further supports this conclusion.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [2]
  1. New Mexico Consortium, Los Alamos, NM (United States)
  2. Aerospace Corporation, El Segundo, CA (United States)
  3. New Mexico Consortium, Los Alamos, NM (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Univ. of New Hampshire, Durham, NH (United States). Inst. for the Study of Earth, Oceans and Space
  5. Univ. of Colorado, Boulder, CO (United States). Lab. for Atmospheric and Space Sciences
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:
1485390
Report Number(s):
LA-UR-18-25084
Journal ID: ISSN 0094-8276
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 45; Journal Issue: 11; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Heliospheric and Magnetospheric Physics; Radiation Belt; Phase Space Density; Local Acceleration; Van Allen Probes; THEMIS

Citation Formats

Boyd, A. J., Turner, D. L., Reeves, G. D., Spence, H. E., Baker, D. N., and Blake, J. B. What Causes Radiation Belt Enhancements: A Survey of the Van Allen Probes Era. United States: N. p., 2018. Web. doi:10.1029/2018GL077699.
Boyd, A. J., Turner, D. L., Reeves, G. D., Spence, H. E., Baker, D. N., & Blake, J. B. What Causes Radiation Belt Enhancements: A Survey of the Van Allen Probes Era. United States. doi:10.1029/2018GL077699.
Boyd, A. J., Turner, D. L., Reeves, G. D., Spence, H. E., Baker, D. N., and Blake, J. B. Tue . "What Causes Radiation Belt Enhancements: A Survey of the Van Allen Probes Era". United States. doi:10.1029/2018GL077699. https://www.osti.gov/servlets/purl/1485390.
@article{osti_1485390,
title = {What Causes Radiation Belt Enhancements: A Survey of the Van Allen Probes Era},
author = {Boyd, A. J. and Turner, D. L. and Reeves, G. D. and Spence, H. E. and Baker, D. N. and Blake, J. B.},
abstractNote = {We survey radiation belt enhancement events during the Van Allen Probes era to determine what mechanism is the dominant cause of enhancements and where it is most effective. Two primary mechanisms have been proposed: (1) betatron/Fermi acceleration due to the Earthward radial transport of electrons, which produces monotonic gradients in phase space density (PSD), and (2) “local acceleration” due to gyro/Landau resonant interaction with electromagnetic waves, which produces radially localized growing peaks in PSD. Here, to differentiate between these processes, we examine radial profiles of PSD in adiabatic coordinates using data from the Van Allen Probes and Time History of Events and Macroscale Interactions during Substorms satellites for 80 outer belt enhancement events from October 2012 to April 2017. Here, this study shows that local acceleration is the dominant acceleration mechanism for MeV electrons in the outer belt, with 87% of the enhancement events exhibiting growing peaks. The strong correlation of the location of these with geomagnetic activity further supports this conclusion.},
doi = {10.1029/2018GL077699},
journal = {Geophysical Research Letters},
number = 11,
volume = 45,
place = {United States},
year = {2018},
month = {6}
}

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Cited by: 11 works
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