Journal article
Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC waves, ULF pulsations, and an electron flux dropout
Journal of geophysical research. Space physics, Vol.121(3), pp.1990-2008
01/22/2016
DOI: 10.1002/2014JA020877
Abstract
We 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.
Details
- Title: Subtitle
- Van Allen Probes, THEMIS, GOES, and Cluster Observations of EMIC waves, ULF pulsations, and an electron flux dropout
- Creators
- K Sigsbee - University of IowaCa Kletzing - University of IowaCw Smith - University of New HampshireR Macdowall - Goddard Space Flight CenterH Spence - University of New HampshireG Reeves - Los Alamos National LaboratoryJb Blake - The Aerospace CorporationDn Baker - University of Colorado BoulderJc Green - Space Hazards Applications Golden Colorado USAHj Singer - National Oceanic and Atmospheric AdministrationCm Carr - Imperial College LondonO Santolik - Charles University
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.121(3), pp.1990-2008
- Publisher
- American Geophysical Union (AGU)
- DOI
- 10.1002/2014JA020877
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Grant note
- DOI: 10.13039/100000104, name: National Aeronautics and Space Administration, award: NAS5‐01072, NAS5‐01072, NAS5‐02099
- Language
- English
- Date published
- 01/22/2016
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199957702771
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