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Observations of a High-Latitude Stable Electron Auroral Emission at Approximately 16 MLT During a Large SubstormDuring an interval when the interplanetary magnetic field was large and primarily duskward and southward, a stable region of auroral emission was observed on 17 August 2001 by IMAGE at 16 magnetic local time, poleward of the main aurora, for 1 h, from before the onset of a large substorm through the recovery phase. In a region where ions showed the energy dispersion expected for the cusp, strong field \aligned currents and Poynting flux were observed by Polar (at 1.8 RE in the Southern Hemisphere) as it transited field lines mapping to the auroral spot in the Northern Hemisphere. The data are consistent with the hypothesis that the long \lasting electron auroral spot maps to the magnetopause region where reconnection was occurring. Under the assumption of conjugacy between the Northern and Southern hemispheres on these field lines, the Polar data suggest that the electrons on these field lines were accelerated by Alfven waves and/or a quasi \static electric field, primarily at altitudes below a few RE since the in situ Poynting flux (mapped to 100 km) is comparable to the energy flux of the emission while the mapped in situ electron energy flux is much smaller. This event provides the first example of an emission due to electrons accelerated at low altitudes at the foot point of a region of quasi \steady dayside reconnection. Cluster data in the magnetotail indicate that the Poynting flux from the reconnection region during this substorm is large enough to account for the observed nightside aurora.
Document ID
20110015526
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Cattell, C.
(Minnesota Univ. Minneapolis, MN, United States)
Dombeck, J.
(Minnesota Univ. Minneapolis, MN, United States)
Preiwisch, A.
(Minnesota Univ. Minneapolis, MN, United States)
Thaller, S.
(Minnesota Univ. Minneapolis, MN, United States)
Vo, P.
(Minnesota Univ. Minneapolis, MN, United States)
Wilson, L. B., III
(Minnesota Univ. Minneapolis, MN, United States)
Wygant, J.
(Minnesota Univ. Minneapolis, MN, United States)
Mende, S. B.
(California Univ. Berkeley, CA, United States)
Frey, H. U.
(California Univ. Berkeley, CA, United States)
Ilie, R.
(Michigan Univ. Ann Arbor, MI, United States)
Lu, G.
(National Center for Atmospheric Research Boulder, CO, United States)
Date Acquired
August 25, 2013
Publication Date
January 1, 2011
Publication Information
Publication: Journal of Geophysical Research
Volume: 116
Subject Category
Geophysics
Report/Patent Number
GSFC.JA.4941.2011
Funding Number(s)
CONTRACT_GRANT: NNX07AL088G
CONTRACT_GRANT: NNX08AH84G
CONTRACT_GRANT: NNG04GG83G
CONTRACT_GRANT: NNX09AE41G
CONTRACT_GRANT: NNX08AQ15G
CONTRACT_GRANT: NNX08AF28G
Distribution Limits
Public
Copyright
Other

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