First E region observations of mesoscale neutral wind interaction with auroral arcs

Kosch, Mike J. and Anderson, C. and Makarevich, R. A. and Carter, B. A. and Fiori, R. A. D. and Conde, M. and Dyson, P. L. and Davies, T. (2010) First E region observations of mesoscale neutral wind interaction with auroral arcs. Journal of Geophysical Research, 115 (A02303). pp. 1-13. ISSN 0148-0227

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Abstract

We report the first observations of E region neutral wind fields and their interaction with auroral arcs at mesoscale spatial resolution during geomagnetically quiet conditions at Mawson, Antarctica. This was achieved by using a scanning Doppler imager, which can observe thermospheric neutral line-of-sight winds and temperatures simultaneously over a wide field of view. In two cases, the background E region wind field was perpendicular to an auroral arc, which when it appeared caused the wind direction within ∼50 km of the arc to rotate parallel along the arc, reverting to the background flow direction when the arc disappeared. This was observed under both westward and eastward plasma convection. The wind rotations occurred within 7–16 min. In one case, as an auroral arc propagated from the horizon toward the local zenith, the background E region wind field became significantly weaker but remained unaffected where the arc had not passed through. We demonstrate through modeling that these effects cannot be explained by height changes in the emission layer. The most likely explanation seems to be the greatly enhanced ion drag associated with the increased plasma density and localized ionospheric electric field associated with auroral arcs. In all cases, the F region neutral wind appeared less affected by the auroral arc, although its presence is clear in the data.

Item Type: Journal Article
Journal or Publication Title: Journal of Geophysical Research
Additional Information: Copyright (2010) American Geophysical Union. Further reproduction or electronic distribution is not permitted
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/1900/1912
Subjects:
Departments: Faculty of Science and Technology > School of Computing & Communications
Faculty of Science and Technology > Physics
ID Code: 31724
Deposited By: Dr Steve Marple
Deposited On: 05 Feb 2010 08:37
Refereed?: Yes
Published?: Published
Last Modified: 14 Oct 2019 12:12
URI: https://eprints.lancs.ac.uk/id/eprint/31724

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