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Are Dawn Storms Jupiter's auroral substorms?
  • +15
  • Bertrand Bonfond,
  • Zhonghua Yao,
  • Randy Gladstone,
  • Denis Grodent,
  • Jean-Claude GERARD,
  • Jessy Matar,
  • Thomas Greathouse,
  • Vincent Hue,
  • Maarten Versteeg,
  • Joshua Kammer,
  • Chihiro Tao,
  • Marissa Vogt,
  • Alessandro Mura,
  • Alberto Adriani,
  • Barry Mauk,
  • William Kurth,
  • Scott Bolton,
  • Rohini Giles
Bertrand Bonfond
Université de Liège, Université de Liège

Corresponding Author:[email protected]

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Zhonghua Yao
University of Liege, University of Liege
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Randy Gladstone
Southwest Research Institute, Southwest Research Institute
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Denis Grodent
Université de Liège, Université de Liège
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Jean-Claude GERARD
Université de Liège, Université de Liège
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Jessy Matar
Université de Liège, Université de Liège
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Thomas Greathouse
Southwest Research Institute, Southwest Research Institute
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Vincent Hue
Southwest Research Institute, Southwest Research Institute
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Maarten Versteeg
Southwest Research Institute, Southwest Research Institute
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Joshua Kammer
Southwest Research Institute, Southwest Research Institute
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Chihiro Tao
National Institute of Information and Communications Technology, National Institute of Information and Communications Technology
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Marissa Vogt
Boston University, Boston University
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Alessandro Mura
Istituto di Astrofisica e Planetologia Spaziali, Istituto di Astrofisica e Planetologia Spaziali
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Alberto Adriani
Istituto Nazionale di Astrofisica, Istituto Nazionale di Astrofisica
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Barry Mauk
Johns Hopkins University, Johns Hopkins University
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William Kurth
Unversity of Iowa, Unversity of Iowa
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Scott Bolton
Southwest Research Institute, Southwest Research Institute
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Rohini Giles
Southwest Research Institute
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Abstract

Dawn storms are among the brightest events in the Jovian aurorae. Up to now, they had only been observed from Earth-based observatories, only showing the Sun-facing side of the planet. Here we show for the first time global views of the phenomenon, from its initiation to its end and from the nightside of the aurora onto the dayside. Based on Juno's first 20 orbits, some patterns now emerge. Small short-lived spots are often seen for a couple of hours before the main emission starts to brighten and evolve from a straight arc to a more irregular one in the midnight sector. As the whole feature rotates dawn-ward, the arc then separates into two arcs with a central initially void region that is progressively filled with emissions. A gap in longitude then often forms before the whole feature dims. Finally, it transforms into an equatorward-moving patch of auroral emissions associated with plasma injection signatures. Some dawn storms remain weak and never fully develop. We also found cases of successive dawn storms within a few hours. Dawn storm thus share many fundamental features with the auroral signatures of the substorms at Earth. These findings demonstrate that, whatever their sources, mass and energy do not always circulate smoothly in planetary magnetospheres. Instead they often accumulate until the magnetospheres reconfigure and generate substorm-like responses in the planetary aurorae, although the temporal and spatial scales are different for different planets.
Mar 2021Published in AGU Advances volume 2 issue 1. 10.1029/2020AV000275