title: Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope.
abstract: We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts of auroral emission observed at the poleward boundary of a solar wind-induced auroral storm, propagating at ∼330% rigid corotation from near ∼01 h LT toward ∼08 h LT. We suggest that these are indicative of ongoing, bursty reconnection of lobe flux in the magnetotail, providing strong evidence that Saturn's auroral storms are caused by large-scale flux closure. We also discuss the later evolution of a similar storm and show that the emission maps to the trailing region of an energetic neutral atom enhancement. We thus identify the auroral form with the upward field-aligned continuity currents flowing into the associated partial ring current.
authors.affiliation: Department of Physics and Astronomy, University of Leicester Leicester, UK.
authors.forename: J D
authors.initials: JD
authors.lastname: Nichols
authors.affiliation: Department of Physics and Astronomy, University of Leicester Leicester, UK ; Department of Physics, Lancaster University Lancaster, UK.
authors.forename: S V
authors.initials: SV
authors.lastname: Badman
authors.affiliation: Space Science and Engineering Center, University of Wisconsin-Madison Madison, Wisconsin, USA.
authors.forename: K H
authors.initials: KH
authors.lastname: Baines
authors.affiliation: Lunar and Planetary Lab, University of Arizona Tucson, Arizona, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Brown
authors.affiliation: Department of Physics and Astronomy, University of Leicester Leicester, UK.
authors.forename: E J
authors.initials: EJ
authors.lastname: Bunce
authors.affiliation: Center for Space Physics, Boston University Boston, Massachusetts, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Clarke
authors.affiliation: Department of Physics and Astronomy, University of Leicester Leicester, UK.
authors.forename: S W H
authors.initials: SW
authors.lastname: Cowley
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado Boulder Boulder, Colorado, USA.
authors.forename: F J
authors.initials: FJ
authors.lastname: Crary
authors.affiliation: Blackett Laboratory, Imperial College London London, UK.
authors.forename: M K
authors.initials: MK
authors.lastname: Dougherty
authors.affiliation: Laboratoire de Physique Atmospherique et Planetaire, Universite de Liege Liege, Belgium.
authors.forename: J-C
authors.initials: JC
authors.lastname: Gérard
authors.affiliation: Department of Physics and Astronomy, University of Leicester Leicester, UK ; Department of Physics, Lancaster University Lancaster, UK.
authors.forename: A
authors.initials: A
authors.lastname: Grocott
authors.affiliation: Laboratoire de Physique Atmospherique et Planetaire, Universite de Liege Liege, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Grodent
authors.affiliation: Department of Physics and Astronomy, University of Iowa Iowa City, Iowa, USA.
authors.forename: W S
authors.initials: WS
authors.lastname: Kurth
authors.affiliation: Department of Physics and Astronomy, University of Leicester Leicester, UK.
authors.forename: H
authors.initials: H
authors.lastname: Melin
authors.affiliation: Applied Physics Laboratory, Johns Hopkins University Laurel, Maryland, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Mitchell
authors.affiliation: Department of Science, Central Arizona College Coolidge, Arizona, USA.
authors.forename: W R
authors.initials: WR
authors.lastname: Pryor
authors.affiliation: Department of Physics and Astronomy, University of Leicester Leicester, UK.
authors.forename: T S
authors.initials: TS
authors.lastname: Stallard