Modulation of nightside polar patches by substorm activity

Wood, A.G. ORCID: 0000-0002-7527-4757, Pryse, S.E. and Moen, J., 2009. Modulation of nightside polar patches by substorm activity. Annales Geophysicae, 27 (10), pp. 3923-3932. ISSN 0992-7689

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Results are presented from a multi-instrument study showing the influence of geomagnetic substorm activity on the spatial distribution of the high-latitude ionospheric plasma. Incoherent scatter radar and radio tomography measurements on 12 December 2001 were used to directly observe the remnants of polar patches in the nightside ionosphere and to investigate their characteristics. The patches occurred under conditions of IMF Bz negative and IMF By negative. They were attributed to dayside photoionisation transported by the high-latitude convection pattern across the polar cap and into the nighttime European sector. The patches on the nightside were separated by some 5° latitude during substorm expansion, but this was reduced to some 2° when the activity had subsided. The different patch separations resulted from the expansion and contraction of the high-latitude plasma convection pattern on the nightside in response to the substorm activity. The patches of larger separation occurred in the antisunward cross-polar flow as it entered the nightside sector. Those of smaller separation were also in antisunward flow, but close to the equatorward edge of the convection pattern, in the slower, diverging flow at the Harang discontinuity. A patch repetition time of some 10 to 30 min was estimated depending on the phase of the substorm.

Item Type: Journal article
Publication Title: Annales Geophysicae
Creators: Wood, A.G., Pryse, S.E. and Moen, J.
Publisher: Copernicus Publications on behalf of the European Geosciences Union.
Date: 2009
Volume: 27
Number: 10
ISSN: 0992-7689
Rights: © Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 Licence.
Divisions: Schools > School of Science and Technology
Record created by: Jill Tomkinson
Date Added: 04 Mar 2016 14:58
Last Modified: 09 Jun 2017 13:59

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