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Title: The UV aurora and ionospheric flows during flux transfer events
Authors: Neudegg, D. A.
Cowley, Stanley William Herbert
McWilliams, K. A.
Lester, Mark
Yeoman, Timothy Kenneth
Sigwarth, J.
Haerendel, G.
Baumjohann, W.
Auster, U.
Fornacon, K. H.
Georgescu, E.
First Published: 1-Feb-2001
Publisher: European Geosciences Union (EGU), Copernicus Publications
Citation: Annales Geophysicae, 2001, 19 (2), pp. 179-188 (10)
Abstract: Far Ultra Violet (FUV) signatures in the polar ionosphere during a period of magnetopause reconnection are compared with ionospheric flows measured in the cusp ‘throat’ and dusk cell by the CUTLASS Hankasalmi HF radar. Regions of peak FUV emission in the 130.4 nm and 135.6 nm range, observed by the Polar spacecraft’s VIS Earth Camera, consistently lie at the turning point of the flows from the dusk cell, poleward into the throat, and at the equatorward edge of the region of high and varied radar spectral-width associated with the cusp. The Equator-S spacecraft was near the magnetopause at the time of the ionospheric observations and geomagnetically conjugate with the region of ionosphere observed by the radar. Flux transfer events (FTEs), suggestive of bursty reconnection between the IMF and geomagnetic fields, were observed by Equator-S prior to and during the periods of high FUV emission. Enhanced poleward ionospheric flow velocities in the polar cusp region, previously shown to be associated with bursty reconnection, consistently lie poleward of the enhanced FUV optical feature. The enhanced optical feature is consistent with the expected position of the largest upward region 1 field-aligned current, associated with electron precipitation, on the dusk edge of the merging gap. The optical feature moves duskward and equatorward during the course of the reconnection sequence, consistent with expansion of the merging line and the polar cap with newly added open magnetic flux by the FTEs. The DMSP F14 spacecraft passed through the enhanced FUV region and measured strong, structured electron precipitation far greater than in the adjacent regions.
DOI Link: 10.5194/angeo-19-179-2001
ISSN: 0992-7689
eISSN: 1432-0576
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © Author(s) 2001. This work is distributed under the Creative Commons Attribution 3.0 License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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