Evolution of relativistic outer belt electrons during an extended quiescent period

A. N Jaynes; X Li; Q. G Schiller; L. W Blum; D. N Baker; W Tu; D. L Turner; B Ni; J Bortnik; S. G Kanekal; J. B Blake; J Wygant

doi:10.1002/2014JA020125

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Evolution of relativistic outer belt electrons during an extended quiescent period

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Evolution of relativistic outer belt electrons during an extended quiescent period

A. N Jaynes, X Li, Q. G Schiller, L. W Blum, D. N Baker, W Tu, D. L Turner, B Ni, J Bortnik, S. G Kanekal, …

Journal of geophysical research. Space physics, Vol.119(12), pp.9558-9566

12/2014

DOI: 10.1002/2014JA020125

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Abstract

To effectively study loss due to hiss‐driven precipitation of relativistic electrons in the outer radiation belt, it is useful to isolate this loss by studying a time of relatively quiet geomagnetic activity. We present a case of initial enhancement and slow, steady decay of 700 keV–2 MeV electron populations in the outer radiation belt during an extended quiescent period from ∼15 December 2012 to 13 January 2013. We incorporate particle measurements from a constellation of satellites, including the Colorado Student Space Weather Experiment (CSSWE) CubeSat, the Van Allen Probes twin spacecraft, and Time History of Events and Macroscale Interactions during Substorms (THEMIS), to understand the evolution of the electron populations across pitch angle and energy. Additional data from calculated phase space density, as well as hiss and chorus wave data from Van Allen Probes, help complete the picture of the slow precipitation loss of relativistic electrons during a quiet time. Electron loss to the atmosphere during this event is quantified through use of the Loss Index Method, utilizing CSSWE measurements at low Earth orbit. By comparing these results against equatorial Van Allen Probes electron flux data, we conclude the net precipitation loss of the outer radiation belt content to be greater than 92%, suggesting no significant acceleration during this period, and resulting in faster electron loss rates than have previously been reported. Key Points Relativistic e‐lifetimes can be estimated with Loss Index Method Total outer belt precipitation loss in quiet time over 92% Hiss scattering gives shorter lifetimes than current theory

electron lifetime

hiss waves

pitch angle scattering

precipitation loss

radiation belts

Details

Title: Subtitle: Evolution of relativistic outer belt electrons during an extended quiescent period
Creators: A. N Jaynes - University of Colorado Boulder
X Li - University of Colorado Boulder
Q. G Schiller - University of Colorado Boulder
L. W Blum - University of Colorado Boulder
D. N Baker - University of Colorado Boulder
W Tu - Los Alamos National Laboratory
D. L Turner - University of California, Los Angeles
B Ni - Wuhan University
J Bortnik - University of California, Los Angeles
S. G Kanekal - Goddard Space Flight Center
J. B Blake - The Aerospace Corporation
J Wygant - University of Minnesota
Resource Type: Journal article
Publication Details: Journal of geophysical research. Space physics, Vol.119(12), pp.9558-9566
DOI: 10.1002/2014JA020125
ISSN: 2169-9380
eISSN: 2169-9402
Number of pages: 9
Grant note: NASA (NAS5‐01072) Fundamental Research Funds (2042014kf0251) JHU/APL (967399) NASA (NAS5‐02099; NNXX12AJ55G) NSF (AGSW 0940277) NSFC (41204120)
Language: English
Date published: 12/2014
Academic Unit: Physics and Astronomy; University College Courses
Record Identifier: 9984199763702771

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