Co-existing structures from high and low energy precipitation in fine scale aurora
Co-existing structures from high and low energy precipitation in fine scale aurora
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.
aurora, fine scale structure, multispectral observations, high energy precipitation, low energy precipitation, pulsations
Dahlgren, H.
8d021086-b328-46fd-affd-a7c8d2b4687e
Lanchester, B.S.
e864533e-eea0-471f-a3f9-7c70c25be55b
Ivchenko, N.
c892df9e-e2a0-450f-bf77-2673e029f565
Dahlgren, H.
8d021086-b328-46fd-affd-a7c8d2b4687e
Lanchester, B.S.
e864533e-eea0-471f-a3f9-7c70c25be55b
Ivchenko, N.
c892df9e-e2a0-450f-bf77-2673e029f565
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).
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.
Text
highElowE_GRL_postrevision_ePrint.pdf
- Accepted Manuscript
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: 14 Mar 2024 19:09
Export record
Altmetrics
Contributors
Author:
H. Dahlgren
Author:
B.S. Lanchester
Author:
N. Ivchenko
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics