angeo-27-2913-2009.pdf (3.26 MB)
Influences on the radius of the auroral oval
journal contributionposted on 2012-10-24, 09:21 authored by Stephen E. Milan, J. Hutchinson, P. D. Boakes, B. Hubert
We examine the variation in the radius of the auroral oval, as measured from auroral images gathered by the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft, in response to solar wind inputs measured by the Advanced Composition Explorer (ACE) spacecraft for the two year interval June 2000 to May 2002. Our main finding is that the oval radius increases when the ring current, as measured by the Sym-H index, is intensified during geomagnetic storms. We discuss our findings within the context of the expanding/contracting polar cap paradigm, in terms of a modification of substorm onset conditions by the magnetic perturbation associated with the ring current.
PDB was supported by a PPARC/STFC CASE award, grant no. PPA/S/C/2006/04488.
CitationAnnales Geophysicae, 2009, 27 (7), pp. 2913-2924
Published inAnnales Geophysicae
PublisherEuropean Geosciences Union (EGU), Copernicus Publications, Springer Verlag (Germany)