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1. Ion Precipitation Into Io's Poles Driven by a Strong Sub‐Alfvénic Interaction

Author

J. R. Szalay, J. Saur, F. Allegrini, R. W. Ebert, P. W. Valek, G. Clark, K. Accetta, F. Bagenal, S. J. Bolton, P. Damiano, V. Dols, B. Mauk, D. J. McComas, C. Paranicas, Y. Sarkango, D. Strobel, A. H. Sulaiman, and R. J. Wilson

Subjects
Geophysics. Cosmic physics, QC801-809
Abstract

Abstract Juno performed two close flybys of Io and found enhanced field‐aligned proton fluxes are absorbed by Io. These protons are absorbed at mass input rates comparable to previous estimates for hydrogen losses from Io, hence Jupiter is likely the source of hydrogen at Io. The conditions necessary for this to occur are: (a) formation of Alfvén waves at Io, (b) wave‐particle coupling to energize protons, (c) anti‐planetward transport of ions due to the magnetic mirror force and/or parallel acceleration, and (d) strong sub‐Alfvénic interaction slowing the flow connected to Io's fluxtube allowing for sufficient travel time for energized ions to transit to Io. The derived slowdown of ≤12% the upstream value is linked to filamentation within the Alfvén wing. This mechanism is likely operating at all strongly interacting satellites and provides an avenue to transfer material from a planetary body to its satellites, including exoplanets and brown dwarfs.

Published
2024
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2. Jovian High‐Latitude Ionospheric Ions: Juno In Situ Observations

Author

P. W. Valek, F. Allegrini, F. Bagenal, S. J. Bolton, J. E. P. Connerney, R. W. Ebert, T. K. Kim, S. M. Levin, P. Louarn, D. J. Mccomas, J. R. Szalay, M. F. Thomsen, and R. J. Wilson

Subjects
Jupiter, ionosphere, high latitude, ions, in situ, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract The low‐altitude, high‐velocity trajectory of the Juno spacecraft enables the Jovian Auroral Distributions Experiment to make the first in situ observations of the high‐latitude ionospheric plasma. Ions are observed to energies below 1 eV. The high‐latitude ionospheric ions are observed simultaneously with a loss cone in the magnetospheric ions, suggesting precipitating magnetospheric ions contribute to the heating of the upper ionosphere, raising the scale height, and pushing ionospheric ions to altitudes of 0.5 RJ above the planet where they are observed by Jovian Auroral Distributions Experiment. The source of the magnetospheric ions is tied to the Io torus and plasma sheet, indicated by the cutoff seen in both the magnetospheric and ionospheric plasma at the Io M‐shells. Equatorward of the Io M‐shell boundary, the ionospheric ions are not observed, indicating a drop in the scale height of the ionospheric ions at those latitudes.

Published
2019
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5. Pluto's Interaction With Energetic Heliospheric Ions

Author

P. Kollmann, M. E. Hill, R. C. Allen, R. L. McNutt, L. E. Brown, N. P. Barnes, P. Delamere, G. Clark, G. B. Andrews, N. Salazar, J. Westlake, G. Romeo, J. Vandegriff, M. Kusterer, D. Smith, K. Nelson, S. Jaskulek, R. B. Decker, A. F. Cheng, S. M. Krimigis, C. M. Lisse, D. G. Mitchell, H. A. Weaver, H. A. Elliott, E. Fattig, G. R. Gladstone, P. W. Valek, S. Weidner, J. Kammer, F. Bagenal, M. Horanyi, D. Kaufmann, A. Harch, C. B. Olkin, M. R. Piquette, J. R. Spencer, L. A. Young, K. Ennico, M. E. Summers, and S. A. Stern

Published
2019
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7. In Situ Observations Connected to the Io Footprint Tail Aurora

Author

J. R. Szalay, B. Bonfond, F. Allegrini, F. Bagenal, S. Bolton, G. Clark, J. E. P. Connerney, R. W. Ebert, R. E. Ergun, G. R. Gladstone, D. Grodent, G. B. Hospodarsky, V. Hue, W. S. Kurth, S. Kotsiaros, S. M. Levin, P. Louarn, B. Mauk, D. J. McComas, J. Saur, P. W. Valek, and R. J. Wilson

Published
2018
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17. Suprathermal Ions in the Outer Heliosphere

Author

Peter Kollmann, M. E. Hill, R. L. McNutt, L. E. Brown, R. C. Allen, G. Clark, B. Andrews, N. Salazar, J. Westlake, G. Romeo, J. Vandegriff, M. Kusterer, D. Smith, S. Jaskulek, R. Decker, A. F. Cheng, S. M. Krimigis, C. M. Lisse, D. G. Mitchell, H. A. Weaver, P. Delamere, H. A. Elliott, E. Fattig, G. R. Gladstone, P. W. Valek, S. Weidner, F. Bagenal, M. Horányi, J. A. Kammer, D. Kaufmann, C. B. Olkin, M. R. Piquette, J. R. Spencer, A. J. Steffl, S. A. Stern, L. A. Young, K. Ennico, I. R. Linscott, D. F. Strobel, M. E. Summers, and J. R. Szalay

Published
2019
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19. Survey of Juno Observations in Jupiter's Plasma Disk: Density

Author

John E. P. Connerney, D. J. McComas, Steve Levin, Scott Bolton, P. W. Valek, Frederic Allegrini, J. R. Szalay, R. J. Wilson, E. Huscher, Fran Bagenal, and Robert Ebert

Subjects
Physics, Jupiter, Geophysics, Space and Planetary Science, Astronomy, Plasma
Published
2021

20. Pluto's Interaction With Energetic Heliospheric Ions

Author

N. Salazar, N. P. Barnes, Fran Bagenal, Matthew E. Hill, A. Harch, H. A. Elliott, S. A. Stern, M. Kusterer, Ralph L. McNutt, George Clark, David E. Kaufmann, Leslie A. Young, John R. Spencer, Peter Delamere, J. A. Kammer, Mihaly Horanyi, R. B. Decker, Stamatios M. Krimigis, L. E. Brown, P. W. Valek, G. B. Andrews, Jon Vandegriff, Donald G. Mitchell, Robert Allen, Michael E. Summers, Joseph Westlake, Kimberly Ennico, K. S. Nelson, Carey M. Lisse, David J. Smith, Peter Kollmann, Harold A. Weaver, Andrew F. Cheng, G. Romeo, M. R. Piquette, Catherine B. Olkin, S. Weidner, S. E. Jaskulek, G. R. Gladstone, and E. D. Fattig

Subjects
Physics, Pluto, Geophysics, New horizons, Space and Planetary Science, Astrobiology, Ion
Abstract

Pluto energies of a few kiloelectron volts and suprathermal ions with tens of kiloelectron volts and above. We measure this population using the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument on board the New Horizons spacecraft that flew by Pluto in 2015. Even though the measured ions have gyroradii larger than the size of Pluto and the cross section of its magnetosphere, we find that the boundary of the magnetosphere is depleting the energetic ion intensities by about an order of magnitude close to Pluto. The intensity is increasing exponentially with distance to Pluto and reaches nominal levels of the interplanetary medium at about 190

Published
2019

21. Proton Outflow Associated With Jupiter's Auroral Processes

Author

Robert Ebert, P. W. Valek, R. J. Wilson, Fran Bagenal, John E. P. Connerney, David J. McComas, Robert E. Ergun, George Clark, Jamey Szalay, Barry Mauk, Scott Bolton, and Frederic Allegrini

Subjects
Jupiter, Physics, Geophysics, Proton, General Earth and Planetary Sciences, Astronomy, Outflow
Published
2021

23. First Report of Electron Measurements During a Europa Footprint Tail Crossing by Juno

Author

Frederic Allegrini, Robert Ebert, R. J. Wilson, G. R. Gladstone, Thomas K. Greathouse, Vincent Hue, George Clark, P. Louarn, Barry Mauk, George Hospodarsky, Fran Bagenal, Scott Bolton, John E. P. Connerney, Jamey Szalay, Masafumi Imai, Joachim Saur, P. W. Valek, William S. Kurth, Ali Sulaiman, D. J. McComas, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Footprint (electronics), Physics, Geophysics, [SDU]Sciences of the Universe [physics], electrons, General Earth and Planetary Sciences, Jupiter aurora, Europa footprint tail, Electron, Atomic physics
Abstract

International audience; We report the first in situ observations of electron measurements at a Europa footprint tail (FPT) crossing in the auroral region. During its 12th science perijove pass, Juno crossed magnetic field lines connected to Europa's FPT. We find that electrons in the range ~0.4 to ~25 keV, with a characteristic energy of 3.6 ± 0.5 keV, precipitate into Jupiter's atmosphere to create the footprint aurora. The energy flux peaks at ~36 mW/m2, while the peak ultraviolet (UV) brightness is estimated at 37 kR. We estimate the peak electron density and temperature to be 17.3 cm-3 and 1.8 ± 0.1 keV, respectively. Using magnetic flux shell mapping, we estimate that the radial width of the interaction at Europa's orbit spans roughly 3.6 ± 1.0 Europa radii. In contrast to typical Io FPT crossings, the instrument background caused by penetrating energetic radiation (> ~5-10 MeV electrons) increased during the Europa FPT crossing.

Published
2020

24. Juno In Situ Observations Above the Jovian Equatorial Ionosphere

Author

Robert Ebert, Jamey Szalay, Frederic Allegrini, John E. P. Connerney, Fran Bagenal, Robert J. Wilson, Scott Bolton, David J. McComas, and P. W. Valek

Subjects
In situ, Physics, Jupiter, Geophysics, General Earth and Planetary Sciences, Ionosphere, Jovian, Astrobiology
Published
2020

25. Chandra observations of Jupiter's X-ray auroral emission during Juno apojove 2017

Author

Frederic Allegrini, Robert Ebert, George Clark, Affelia Wibisono, Michelle F. Thomsen, Caitriona M. Jackman, Diego Altamirano, P. W. Valek, G. Branduardi-Raymont, G. R. Gladstone, Marissa F. Vogt, Dale Weigt, William Dunn, and Ralph P. Kraft

Subjects
Physics, Magnetosphere, Static timing analysis, Astrophysics, Jovian, Latitude, symbols.namesake, Geophysics, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), symbols, Polar, Magnetopause, Rayleigh scattering, Longitude
Abstract

Jupiter's auroral X-rays have been observed for 40 years with an unknown driver producing quasiperiodic emission, concentrated into auroral hot spots. In this study we analyze an (Formula presented.) 10-hr Chandra observation from 18:56 on 18 June 2017. We use a new Python pipeline to analyze the auroral morphology, perform timing analysis by incorporating Rayleigh testing, and use in situ Juno observations to infer the magnetosphere that was compressed during the Chandra interval. During this time Juno was near its apojove position of (Formula presented.) 112 (Formula presented.), on the dawn flank of the magnetosphere near the nominal magnetopause position. We present new dynamical polar plots showing an extended X-ray hot spot in the northern auroral region traversing across the Jovian disk. From this morphology, we propose setting a numerical threshold of (Formula presented.) 7 photons per 5° System III longitude (Formula presented.) 5° latitude to define a photon concentration of the northern hot spot region. Our timing analysis finds two significant quasiperiodic oscillations (QPOs) of (Formula presented.) 37 and (Formula presented.) 26 min within the extended northern hot spot. No statistically significant QPOs were found in the southern X-ray auroral emission. The Rayleigh test is combined with Monte Carlo simulation to find the statistical significance of any QPOs found. We use a flux equivalence mapping model to trace the possible origin of the QPOs, and thus the driver, to the dayside magnetopause boundary.

Published
2020

26. Survey of Ion Properties in Jupiter's Plasma Sheet: Juno JADE‐I Observations

Author

D. J. McComas, George Livadiotis, R. J. Wilson, Michelle F. Thomsen, P. W. Valek, Robert Ebert, T. K. Kim, Scott Bolton, Fran Bagenal, John E. P. Connerney, and Frederic Allegrini

Subjects
Physics, Jupiter, Geophysics, Space and Planetary Science, Plasma sheet, Astronomy, JADE (particle detector), Ion
Published
2020

28. Energy Flux and Characteristic Energy of Electrons Over Jupiter's Main Auroral Emission

Author

R. J. Wilson, G. R. Gladstone, John E. P. Connerney, D. J. McComas, P. W. Valek, Scott Bolton, Fran Bagenal, Jamey Szalay, Robert Ebert, Barry Mauk, Vincent Hue, William S. Kurth, Masafumi Imai, Thomas K. Greathouse, Bertrand Bonfond, Frederic Allegrini, George Clark, Steve Levin, P. Louarn, Joachim Saur, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
electron, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Energy flux, Magnetosphere, aurora, Electron, Astrophysics, JADE (particle detector), Jupiter, Geophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Physics::Space Physics, magnetosphere, Characteristic energy
Abstract

International audience; Jupiter's ultraviolet (UV) aurorae, the most powerful and intense in the solar system, are caused by energetic electrons precipitating from the magnetosphere into the atmosphere where they excite the molecular hydrogen. Previous studies focused on case analyses and/or greater than 30-keV energy electrons. Here for the first time we provide a comprehensive evaluation of Jovian auroral electron characteristics over the entire relevant range of energies (~100 eV to ~1 MeV). The focus is on the first eight perijoves providing a coarse but complete System III view of the northern and southern auroral regions with corresponding UV observations. The latest magnetic field model JRM09 with a current sheet model is used to map Juno's magnetic foot point onto the UV images and relate the electron measurements to the UV features. We find a recurring pattern where the 3- to 30-keV electron energy flux peaks in a region just equatorward of the main emission. The region corresponds to a minimum of the electron characteristic energy (J. Outside that region, the >100-keV electrons contribute to most (>~70-80%) of the total downward energy flux and the characteristic energy is usually around 100 keV or higher. We examine the UV brightness per incident energy flux as a function of characteristic energy and compare it to expectations from a model.

Published
2020

29. Whistler Mode Waves Associated With Broadband Auroral Electron Precipitation at Jupiter

Author

Frederic Allegrini, George Hospodarsky, Steven Levin, S. S. Elliott, Barry Mauk, Ondrej Santolik, Scott Bolton, John E. P. Connerney, G. R. Gladstone, D. A. Gurnett, P. W. Valek, and William S. Kurth

Subjects
Jupiter, Physics, Geophysics, 010504 meteorology & atmospheric sciences, 0103 physical sciences, Broadband, General Earth and Planetary Sciences, Astronomy, Electron precipitation, Whistler mode, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published
2018

30. The Acceleration of Electrons to High Energies Over the Jovian Polar Cap via Whistler Mode Wave‐Particle Interactions

Author

P. W. Valek, S. S. Elliott, Barry Mauk, Robert Ebert, William S. Kurth, George Clark, Frederic Allegrini, D. A. Gurnett, and Scott Bolton

Subjects
Physics, 010504 meteorology & atmospheric sciences, Electron, 01 natural sciences, Jovian, Computational physics, Acceleration, Geophysics, Wave–particle duality, Space and Planetary Science, 0103 physical sciences, Whistler mode, Polar cap, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Published
2018

31. Empirical Characterization of Low-Altitude Ion Flux Derived from TWINS

Author

David J. McComas, P. W. Valek, Kristie LLera, Jerry Goldstein, and Jillian Redfern

Subjects
Low altitude, Materials science, 010504 meteorology & atmospheric sciences, Energetic neutral atom, Precipitation (chemistry), Flux, 01 natural sciences, Molecular physics, Ion, Characterization (materials science), Geophysics, Space and Planetary Science, 0103 physical sciences, 010303 astronomy & astrophysics, Ring current, 0105 earth and related environmental sciences
Published
2018

32. Diverse Electron and Ion Acceleration Characteristics Observed Over Jupiter's Main Aurora

Author

G. R. Gladstone, John E. P. Connerney, Robert Ebert, George Clark, Peter Kollmann, Steven Levin, Alberto Adriani, Frederic Allegrini, P. W. Valek, D. A. Ranquist, J. M. Peachey, Barry Mauk, William S. Kurth, D. J. McComas, Bertrand Bonfond, Scott Bolton, Chris Paranicas, Abigail Rymer, Dennis Haggerty, and Fran Bagenal

Subjects
Jupiter, Physics, Geophysics, 010504 meteorology & atmospheric sciences, 0103 physical sciences, General Earth and Planetary Sciences, Magnetosphere, Electron, Astrophysics, Ion acceleration, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published
2018

33. Jovian bow shock and magnetopause encounters by the Juno spacecraft

Author

David J. McComas, Steven Levin, Frederic Allegrini, John E. P. Connerney, Scott Bolton, Robert Ebert, Abigail Rymer, George Clark, Chris Paranicas, P. W. Valek, William S. Kurth, George Hospodarsky, and Dennis Haggerty

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astronomy, Magnetosphere, Geophysics, Bow shocks in astrophysics, 01 natural sciences, Jovian, Jupiter, Orbit, Solar wind, Local time, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

The Juno spacecraft has crossed Jupiter's bow shock (BS) and magnetopause (MP) multiple times in the dawn sector (near 0600 local time), both during the approach to Jupiter and during the first three apojove periods. A survey of all of these crossings using the Juno field and particle instruments has been performed, with 51 bow shock and 97 magnetopause crossings being detected. The BS crossings ranged from 92 to 128 RJ with 1 encounter during the approach, 36 during the first apojove period, 0 on the second, and 14 during the third. The MP crossings ranged from 73 to 114 RJ, with 8 MP encounters during the approach, 40 encounters during the first apojove period, 24 encounters on the second, and 46 during the third. During the approach, Juno initially encountered an expanding magnetosphere resulting in a single BS and MP crossing, followed a few days later by a contracting magnetosphere, resulting in 7 more MP crossings and a BS crossing on the first outbound orbit at 92 RJ. The lack of BS crossings and the limited number of MP crossings during the second apojove period suggests a long period of an expanded magnetosphere, likely caused by a prolonged period of low solar wind dynamic pressure associated with a rarefaction region. The detection of BS crossings on the third apojove period suggests another period of a highly compressed magnetosphere.

Published
2017

34. Jovian High‐Latitude Ionospheric Ions: Juno In Situ Observations

Author

John E. P. Connerney, Steve Levin, Michelle F. Thomsen, P. Louarn, Robert Ebert, T. K. Kim, Jamey Szalay, R. J. Wilson, P. W. Valek, Frederic Allegrini, Fran Bagenal, D. J. McComas, Scott Bolton, Southwest Research Institute [San Antonio] (SwRI), The University of Texas at San Antonio (UTSA), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), Space Systems Research Corporation (SSRC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Princeton University, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
In situ, Physics, 010504 meteorology & atmospheric sciences, Astronomy, 7. Clean energy, 01 natural sciences, Jovian, Ion, Physics::Geophysics, Jupiter, Geophysics, 13. Climate action, Physics::Plasma Physics, [SDU]Sciences of the Universe [physics], High latitude, 0103 physical sciences, Physics::Space Physics, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; The lowaltitude, highvelocity trajectory of the Juno spacecraft enables the Jovian Auroral Distributions Experiment to make the rst in situ observations of the highlatitude ionospheric plasma. Ions are observed to energies below 1 eV. The highlatitude ionospheric ions are observed simultaneously with a loss cone in the magnetospheric ions, suggesting precipitating magnetospheric ions contribute to the heating of the upper ionosphere, raising the scale height, and pushing ionospheric ions to altitudes of 0.5 RJ above the planet where they are observed by Jovian Auroral Distributions Experiment. The source of the magnetospheric ions is tied to the Io torus and plasma sheet, indicated by the cutoff seen in both the magnetospheric and ionospheric plasma at the Io Mshells. Equatorward of the Io Mshell boundary, the ionospheric ions are not observed, indicating a drop in the scale height of the ionospheric ions at those latitudes.

Published
2019

35. Comparing Electron Energetics and UV Brightness in Jupiter's Northern Polar Region During Juno Perijove 5

Author

Fran Bagenal, G. R. Gladstone, Steven Levin, Barry Mauk, Thomas K. Greathouse, Vincent Hue, P. Louarn, R. J. Wilson, Michelle F. Thomsen, Jamey Szalay, John E. P. Connerney, Robert Ebert, Masafumi Imai, P. W. Valek, George Clark, William S. Kurth, Frederic Allegrini, David J. McComas, Scott Bolton, Chris Paranicas, Southwest Research Institute [San Antonio] (SwRI), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), Department of Nuclear Engineering, Kyoto University, ECLIPSE 2015, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Iowa [Iowa City], Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Princeton University, Institut de médecine moléculaire de Rangueil (I2MR), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées- Institut Fédératif de Recherche Bio-médicale Institution (IFR150)-Institut National de la Santé et de la Recherche Médicale (INSERM), School of Social and Community Medicine [Bristol], University of Bristol [Bristol], Louarn, Philippe, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)- Institut Fédératif de Recherche Bio-médicale Institution (IFR150)-Institut National de la Santé et de la Recherche Médicale (INSERM), Kyoto University [Kyoto], Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-IFR150-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
Juno, Brightness, Jupiter's aurora, 010504 meteorology & atmospheric sciences, polar auroral region, Astrophysics::High Energy Astrophysical Phenomena, Energy flux, Electron, Astrophysics, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], 7. Clean energy, 01 natural sciences, Jupiter, [SDU] Sciences of the Universe [physics], Planetary Sciences: Solar System Objects, Flux (metallurgy), Altitude, Aurorae, 0103 physical sciences, Research Letter, Magnetospheric Physics, 010303 astronomy & astrophysics, Planetary Sciences: Fluid Planets, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, electron energy flux, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Energetics, Planetary Magnetospheres, Energetic Particles: Precipitating, Polar Regions, Research Letters, polar UV emissions, Geophysics, Magnetospheres, precipitating electrons, 13. Climate action, [SDU]Sciences of the Universe [physics], Physics::Space Physics, General Earth and Planetary Sciences, Polar, Space Sciences
Abstract

We compare electron and UV observations mapping to the same location in Jupiter's northern polar region, poleward of the main aurora, during Juno perijove 5. Simultaneous peaks in UV brightness and electron energy flux are identified when observations map to the same location at the same time. The downward energy flux during these simultaneous observations was not sufficient to generate the observed UV brightness; the upward energy flux was. We propose that the primary acceleration region is below Juno's altitude, from which the more intense upward electrons originate. For the complete interval, the UV brightness peaked at ~240 kilorayleigh (kR); the downward and upward energy fluxes peaked at 60 and 700 mW/m2, respectively. Increased downward energy fluxes are associated with increased contributions from tens of keV electrons. These observations provide evidence that bidirectional electron beams with broad energy distributions can produce tens to hundreds of kilorayleigh polar UV emissions., Key Points Simultaneous peaks are observed in electron energy flux and UV brightness when they map to same location in Jupiter's polar region at the same timeUpward greater than downward electron energy fluxes are observed, suggesting that primary acceleration region may be below ~1.5 jovian radiiDownward energy fluxes able to produce tens to hundreds of kilorayleigh polar UV emissions are identified; increases in energy flux due to tens of keV electrons

Published
2019

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