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Using spectral characteristics to interpret auroral imaging in the 731.9 nm O+ line

Using spectral characteristics to interpret auroral imaging in the 731.9 nm O+ line
Using spectral characteristics to interpret auroral imaging in the 731.9 nm O+ line
Simultaneous observations were made of dynamic aurora during substorm activity on 26 January 2006 with three high spatial and temporal resolution instruments: the ASK (Auroral Structure and Kinetics) instrument, SIF (Spectrographic Imaging Facility) and ESR (EISCAT Svalbard Radar), all located on Svalbard (78° N, 16.2° E). One of the narrow field of view ASK cameras is designed to detect O+ ion emission at 731.9 nm.

From the spectrographic data we have been able to determine the amount of contaminating N2 and OH emission detected in the same filter. This is of great importance to further studies using the ASK instrument, when the O+ ion emission will be used to detect flows and afterglows in active aurora.

The ratio of O+ to N2 emission is dependent on the energy spectra of electron precipitation, and was found to be related to changes in the morphology of the small-scale aurora. The ESR measured height profiles of electron densities, which allowed estimates to be made of the energy spectrum of the precipitation during the events studied with optical data from ASK and SIF.

It was found that the higher energy precipitation corresponded to discrete and dynamic features, including curls, and low energy precipitation corresponded to auroral signatures that were dominated by rays. The evolution of these changes on time scales of seconds is of importance to theories of auroral acceleration mechanisms.
ionosphere, auroral ionosphere, particle precipitation, instruments and techniques
0992-7689
1905-1917
Dahlgren, H.
8d021086-b328-46fd-affd-a7c8d2b4687e
Ivchenko, N.
c892df9e-e2a0-450f-bf77-2673e029f565
Lanchester, B. S.
e864533e-eea0-471f-a3f9-7c70c25be55b
Sullivan, J.
38fa668a-22be-4479-bcac-5d2b54fa526e
Whiter, D.
9a30d7b6-ea41-44fb-bd52-3ff1964eca5c
Marklund, G.
ca3a83f3-e335-4d69-b5e3-2dad226e339f
Strømme, A.
ac925af6-d999-43f2-8111-75d42287426a
Dahlgren, H.
8d021086-b328-46fd-affd-a7c8d2b4687e
Ivchenko, N.
c892df9e-e2a0-450f-bf77-2673e029f565
Lanchester, B. S.
e864533e-eea0-471f-a3f9-7c70c25be55b
Sullivan, J.
38fa668a-22be-4479-bcac-5d2b54fa526e
Whiter, D.
9a30d7b6-ea41-44fb-bd52-3ff1964eca5c
Marklund, G.
ca3a83f3-e335-4d69-b5e3-2dad226e339f
Strømme, A.
ac925af6-d999-43f2-8111-75d42287426a

Dahlgren, H., Ivchenko, N., Lanchester, B. S., Sullivan, J., Whiter, D., Marklund, G. and Strømme, A. (2008) Using spectral characteristics to interpret auroral imaging in the 731.9 nm O+ line. Annales Geophysicae, 26 (7), 1905-1917.

Record type: Article

Abstract

Simultaneous observations were made of dynamic aurora during substorm activity on 26 January 2006 with three high spatial and temporal resolution instruments: the ASK (Auroral Structure and Kinetics) instrument, SIF (Spectrographic Imaging Facility) and ESR (EISCAT Svalbard Radar), all located on Svalbard (78° N, 16.2° E). One of the narrow field of view ASK cameras is designed to detect O+ ion emission at 731.9 nm.

From the spectrographic data we have been able to determine the amount of contaminating N2 and OH emission detected in the same filter. This is of great importance to further studies using the ASK instrument, when the O+ ion emission will be used to detect flows and afterglows in active aurora.

The ratio of O+ to N2 emission is dependent on the energy spectra of electron precipitation, and was found to be related to changes in the morphology of the small-scale aurora. The ESR measured height profiles of electron densities, which allowed estimates to be made of the energy spectrum of the precipitation during the events studied with optical data from ASK and SIF.

It was found that the higher energy precipitation corresponded to discrete and dynamic features, including curls, and low energy precipitation corresponded to auroral signatures that were dominated by rays. The evolution of these changes on time scales of seconds is of importance to theories of auroral acceleration mechanisms.

Full text not available from this repository.

More information

Published date: 15 July 2008
Keywords: ionosphere, auroral ionosphere, particle precipitation, instruments and techniques

Identifiers

Local EPrints ID: 146803
URI: http://eprints.soton.ac.uk/id/eprint/146803
ISSN: 0992-7689
PURE UUID: 7d1ee056-424f-4edb-a000-4f4dad2510f2
ORCID for D. Whiter: ORCID iD orcid.org/0000-0001-7130-232X

Catalogue record

Date deposited: 22 Apr 2010 13:49
Last modified: 20 Jul 2019 00:50

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