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  • 2016JA023792_accepted_manuscript

    Rights statement: Accepted for publication in Journal of Geophysical Research: Space Physics. Copyright 2017 American Geophysical Union. Further reproduction or electronic distribution is not permitted

    Accepted author manuscript, 4 MB, PDF-document

    Available under license: CC BY-NC: Creative Commons Attribution-NonCommercial 4.0 International License

  • Kinrade_et_al-2017-Journal_of_Geophysical_Research-_Space_Physics

    Rights statement: ©2017. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

    Final published version, 3 MB, PDF-document

    Available under license: CC BY: Creative Commons Attribution 4.0 International License

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An isolated, bright cusp aurora at Saturn

Research output: Contribution to journalJournal article

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<mark>Journal publication date</mark>06/2017
<mark>Journal</mark>Journal of Geophysical Research: Space Physics
Issue number6
Volume122
Number of pages18
Pages (from-to)6121-6138
<mark>State</mark>Published
Early online date30/05/17
<mark>Original language</mark>English

Abstract

Saturn's dayside aurora display a number of morphological features poleward of the main emission region. We present an unusual morphology captured by the Hubble Space Telescope on 14 June 2014 (day 165), where, for two hours, Saturn's FUV aurora faded almost entirely, with the exception of a distinct emission spot at high latitude. The spot remained fixed in local time between 10-15 LT, and moved polewards to a minimum colatitude of ~4°. It was bright and persistent, displaying intensities of up to 49 kR over a lifetime of two hours. Interestingly the spot constituted the entirety of the northern auroral emission, with no emissions present at any other local time – including Saturn's characteristic dawn arc, the complete absence of which is rarely observed. Solar wind parameters from propagation models, together with a Cassini magnetopause crossing and solar wind encounter, indicate that Saturn's magnetosphere was likely to have been embedded in a rarefaction region, resulting in an expanded magnetosphere configuration during the interval. We infer that the spot was sustained by reconnection either poleward of the cusp, or at low latitudes under a strong component of interplanetary magnetic field transverse to the solar wind flow. The subsequent poleward motion could then arise from either reconfiguration of successive open field lines across the polar cap, or convection of newly opened field lines. We also consider the possible modulation of the feature by planetary period rotating current systems.

Bibliographic note

©2017. The Authors.
This is an open access article under the terms of the Creative Commons
Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.