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Co-existing structures from high and low energy precipitation in fine scale aurora

Dahlgren, H., Lanchester, B.S. and Ivchenko, N. (2015) Co-existing structures from high and low energy precipitation in fine scale aurora Geophysical Research Letters (doi:10.1002/2015GL063173).

Record type: Article

Abstract

High resolution multi-monochromatic measurements of auroral emissions have revealed the first optical evidence of coexisting small-scale auroral features resulting from separate high and low energy populations of precipitating electrons on the same field line. The features exhibit completely separate motion and morphology. From emission ratios and ion chemistry modeling, the average energy and energy flux of the precipitation is estimated. The high energy precipitation is found to form large pulsating patches of 0.1 Hz with a 3 Hz modulation, and non-pulsating co-existing discrete auroral filaments. The low energy precipitation is observed simultaneously on the same field line as discrete filaments with no pulsation. The simultaneous structures do not interact, and they drift with different speeds in different directions. We suggest that the high and low energy electron populations are accelerated by separate mechanisms, at different distances from earth. The small scale structures could be caused by local instabilities above the ionosphere.

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More information

Accepted/In Press date: 6 February 2015
e-pub ahead of print date: 10 February 2015
Keywords: aurora, fine scale structure, multispectral observations, high energy precipitation, low energy precipitation, pulsations
Organisations: Astronomy Group

Identifiers

Local EPrints ID: 374583
URI: http://eprints.soton.ac.uk/id/eprint/374583
ISSN: 0094-8276
PURE UUID: 92150d40-58c9-4d28-8197-b321d3e02d50

Catalogue record

Date deposited: 23 Feb 2015 14:06
Last modified: 17 Jul 2017 21:26

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Contributors

Author: H. Dahlgren
Author: B.S. Lanchester
Author: N. Ivchenko

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