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).


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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.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1002/2015GL063173
ISSNs: 0094-8276 (print)
Keywords: aurora, fine scale structure, multispectral observations, high energy precipitation, low energy precipitation, pulsations
Subjects: Q Science > QB Astronomy
Organisations: Astronomy Group
ePrint ID: 374583
Date :
Date Event
6 February 2015Accepted/In Press
10 February 2015e-pub ahead of print
Date Deposited: 23 Feb 2015 14:06
Last Modified: 09 Jun 2017 10:51
Further Information:Google Scholar

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