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Solar illumination control of ionospheric outflow above polar cap arcs

Maes, L., Maggiolo, R., De Keyser, J., Dandouras, I., Fear, R.C., Fontaine, D. and Haaland, S. (2015) Solar illumination control of ionospheric outflow above polar cap arcs Geophysical Research Letters, 42, (5), pp. 1304-1311. (doi:10.1002/2014GL062972).

Record type: Article


We measure the flux density, composition, and energy of outflowing ions above the polar cap, accelerated by quasi-static electric fields parallel to the magnetic field and associated with polar cap arcs, using Cluster. Mapping the spacecraft position to its ionospheric foot point, we analyze the dependence of these parameters on the solar zenith angle (SZA). We find a clear transition at SZA between ?94° and ?107°, with the O+ flux higher above the sunlit ionosphere. This dependence on the illumination of the local ionosphere indicates that significant O+ upflow occurs locally above the polar ionosphere. The same is found for H+, but to a lesser extent. This effect can result in a seasonal variation of the total ion upflow from the polar ionosphere. Furthermore, we show that low-magnitude field-aligned potential drops are preferentially observed above the sunlit ionosphere, suggesting a feedback effect of ionospheric conductivity.

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Accepted/In Press date: 12 February 2015
Published date: 12 March 2015
Organisations: Astronomy Group


Local EPrints ID: 394178
ISSN: 0094-8276
PURE UUID: ad2bf248-ef4d-4e72-89bb-ee304508ba29
ORCID for R.C. Fear: ORCID iD

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Date deposited: 12 May 2016 11:24
Last modified: 17 Jul 2017 19:02

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Author: L. Maes
Author: R. Maggiolo
Author: J. De Keyser
Author: I. Dandouras
Author: R.C. Fear ORCID iD
Author: D. Fontaine
Author: S. Haaland

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