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Nightside ionospheric convection asymmetries during the early substorm expansion phase: relationship to onset local time

Grocott, Adrian and Laurens, Hannah and Wild, James Anderson (2017) Nightside ionospheric convection asymmetries during the early substorm expansion phase: relationship to onset local time. Geophysical Research Letters, 44 (23). pp. 11696-11705. ISSN 0094-8276

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    Abstract

    We present SuperDARN radar observations of ionospheric convection during substorms. Substorms were grouped according to their onset latitude, onset magnetic local time, and the prevailing sense of IMF BY. The radar observations were then sorted according to substorm group and average convection patterns produced. Here, we discuss the patterns corresponding to substorms with onsets occurring in the 65∘−67∘ onset latitude range, at either early (20 − 22h) or late (01 − 03h) magnetic local times, during intervals of either dominant positive or negative IMF BY. We show that the morphology of the convection patterns differs from that predicted by existing empirical models, with the location of the nightside convection throat being largely consistent with the location of substorm onset. The expected IMF BY-induced dawn-dusk convection asymmetry can be enhanced on the nightside when the substorm onset occurs at a fortuitous location, but can equally be removed or even reversed from this expected state. Thus the nightside convection asymmetries are seemingly unrelated to the instantaneous sense of IMF BY.

    Item Type: Journal Article
    Journal or Publication Title: Geophysical Research Letters
    Uncontrolled Keywords: substorm ; convection ; superdarn ; magnetosphere ; ionosphere
    Subjects:
    Departments: Faculty of Science and Technology > Physics
    ID Code: 88693
    Deposited By: ep_importer_pure
    Deposited On: 17 Nov 2017 12:58
    Refereed?: Yes
    Published?: Published
    Last Modified: 21 Sep 2018 01:11
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/88693

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