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Title: On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction

We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ~0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, the moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. Here, we compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDSmore » by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.« less
Authors:
 [1] ;  [1] ; ORCiD logo [2] ;  [1] ;  [1]
  1. Univ. of Alberta, Edmonton, AB (Canada). Dept. of Physics
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-18-20202
Journal ID: ISSN 2169-9380
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research. Space Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 5; Journal ID: ISSN 2169-9380
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Heliospheric and Magnetospheric Physics
OSTI Identifier:
1438365

Olifer, Leonid, Mann, Ian R., Morley, Steven Karl, Ozeke, Louis G., and Choi, D.. On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction. United States: N. p., Web. doi:10.1029/2018JA025190.
Olifer, Leonid, Mann, Ian R., Morley, Steven Karl, Ozeke, Louis G., & Choi, D.. On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction. United States. doi:10.1029/2018JA025190.
Olifer, Leonid, Mann, Ian R., Morley, Steven Karl, Ozeke, Louis G., and Choi, D.. 2018. "On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction". United States. doi:10.1029/2018JA025190.
@article{osti_1438365,
title = {On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction},
author = {Olifer, Leonid and Mann, Ian R. and Morley, Steven Karl and Ozeke, Louis G. and Choi, D.},
abstractNote = {We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ~0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, the moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. Here, we compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.},
doi = {10.1029/2018JA025190},
journal = {Journal of Geophysical Research. Space Physics},
number = 5,
volume = 123,
place = {United States},
year = {2018},
month = {4}
}