Juno observations of energetic charged particles over Jupiter's polar regions: Analysis of monodirectional and bidirectional electron beams
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- B. H. Mauk
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
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- D. K. Haggerty
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
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- C. Paranicas
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
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- G. Clark
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
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- P. Kollmann
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
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- A. M. Rymer
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
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- D. G. Mitchell
- Applied Physics Laboratory The Johns Hopkins University Laurel Maryland USA
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- S. J. Bolton
- Southwest Research Institute San Antonio Texas USA
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- S. M. Levin
- Jet Propulsion Laboratory Pasadena California USA
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- A. Adriani
- Istituto di Astrofisica e Planetologia Spaziali Istituto Nazionale di Astrofisica Roma Italy
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- F. Allegrini
- Southwest Research Institute San Antonio Texas USA
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- F. Bagenal
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder Colorado USA
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- J. E. P. Connerney
- NASA Goddard Space Flight Center Greenbelt Maryland USA
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- G. R. Gladstone
- Southwest Research Institute San Antonio Texas USA
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- W. S. Kurth
- Department of Physics and Astronomy University of Iowa Iowa City Iowa USA
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- D. J. McComas
- Southwest Research Institute San Antonio Texas USA
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- D. Ranquist
- Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder Colorado USA
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- J. R. Szalay
- Southwest Research Institute San Antonio Texas USA
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- P. Valek
- Southwest Research Institute San Antonio Texas USA
説明
<jats:title>Abstract</jats:title><jats:p>Juno obtained unique low‐altitude space environment measurements over Jupiter's poles on 27 August 2016. Here Jupiter Energetic‐particle Detector Instrument observations are presented for electrons (25–800 keV) and protons (10–1500 keV). We analyze magnetic field‐aligned electron angular beams over expected auroral regions that were sometimes symmetric (bidirectional) but more often strongly asymmetric. Included are variable but surprisingly persistent upward, monodirectional electron angular beams emerging from what we term the “polar cap,” poleward of the nominal auroral ovals. The energy spectra of all beams were monotonic and hard (not structured in energy), showing power law‐like distributions often extending beyond ~800 keV. Given highly variable downward energy fluxes (below 1 <jats:italic>R<jats:sub>J</jats:sub></jats:italic> altitudes within the loss cone) as high as 280 mW/m<jats:sup>2</jats:sup>, we suggest that mechanisms generating these beams are among the primary processes generating Jupiter's uniquely intense auroral emissions, distinct from what is typically observed at Earth.</jats:p>
収録刊行物
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- Geophysical Research Letters
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Geophysical Research Letters 44 (10), 4410-4418, 2017-05-25
American Geophysical Union (AGU)