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Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC Waves, ULF Pulsations, and an Electron Flux DropoutWe examined an electron flux dropout during the 12-14 November 2012 geomagnetic storm using observations from seven spacecraft: the two Van Allen Probes, Time History of Events and Macroscale Interactions during Substorms (THEMIS)-A (P5), Cluster 2, and Geostationary Operational Environmental Satellites (GOES) 13, 14, and 15. The electron fluxes for energies greater than 2.0 MeV observed by GOES 13, 14, and 15 at geosynchronous orbit and by the Van Allen Probes remained at or near instrumental background levels for more than 24 h from 12 to 14 November. For energies of 0.8 MeV, the GOES satellites observed two shorter intervals of reduced electron fluxes. The first interval of reduced 0.8 MeV electron fluxes on 12-13 November was associated with an interplanetary shock and a sudden impulse. Cluster, THEMIS, and GOES observed intense He+ electromagnetic ion cyclotron (EMIC) waves from just inside geosynchronous orbit out to the magnetopause across the dayside to the dusk flank. The second interval of reduced 0.8 MeV electron fluxes on 13-14 November was associated with a solar sector boundary crossing and development of a geomagnetic storm with Dst<100 nT. At the start of the recovery phase, both the 0.8 and 2.0 MeV electron fluxes finally returned to near prestorm values, possibly in response to strong ultralow frequency (ULF) waves observed by the Van Allen Probes near dawn. A combination of adiabatic effects, losses to the magnetopause, scattering by EMIC waves, and acceleration by ULF waves can explain the observed electron behavior.
Document ID
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Sigsbee, K.
(Iowa Univ. Iowa City, IA, United States)
Kletzing, C. A.
(Iowa Univ. Iowa City, IA, United States)
Smith, C. W.
(New Hampshire Univ. Durham, NH, United States)
Macdowall, R.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Spence, H.
(New Hampshire Univ. Durham, NH, United States)
Reeves, G.
(Los Alamos National Lab. NM, United States)
Blake, J. B.
(Aerospace Corp. El Segundo, CA, United States)
Baker, D. N.
(Colorado Univ. Boulder, CO, United States)
Green, J. C.
(Space Hazards Applications Golden, CO, United States)
Singer, H. J.
(National Oceanic and Atmospheric Administration Boulder, CO, United States)
Carr, C.
(Imperial Coll. of London London, United Kingdom)
Santolík, O.
(Karlova Univ. Prague, Czechoslovakia)
Date Acquired
March 21, 2017
Publication Date
March 4, 2016
Publication Information
Publication: Journal of Geophysical Research: Space Physics
Publisher: AGU Publications
Volume: 121
Issue: 3
ISSN: 2169-9380
e-ISSN: 2169-9402
Subject Category
Report/Patent Number
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