20 results on '"Robert Ebert"'
Search Results
2. Observation of Kolmogorov Turbulence in the Jovian Magnetosheath From JADE Data
- Author
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David J. McComas, J. R. Szalay, Riddhi Bandyopadhyay, Scott Bolton, Frederic Allegrini, D. J. Gershman, R. J. Wilson, and Robert Ebert
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Physics ,Geophysics ,Magnetosheath ,Turbulence ,General Earth and Planetary Sciences ,Astrophysics ,JADE (particle detector) ,Jovian - Published
- 2021
3. Energy Spectra Near Ganymede From Juno Data
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Dennis Haggerty, John E. P. Connerney, Robert Ebert, Chris Paranicas, Barry Mauk, Joseph Westlake, Peter Kollmann, Jamey Szalay, Frederic Allegrini, George Clark, and Scott Bolton
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Physics ,Geophysics ,General Earth and Planetary Sciences ,Magnetosphere ,Astrophysics ,Albedo ,Spectral line ,Energy (signal processing) - Published
- 2021
4. Proton Outflow Associated With Jupiter's Auroral Processes
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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
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Jupiter ,Physics ,Geophysics ,Proton ,General Earth and Planetary Sciences ,Astronomy ,Outflow - Published
- 2021
5. A Persistent Depletion of Plasma Ions Within Jupiter's Auroral Polar Caps
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Fran Bagenal, Craig J. Pollock, Frederic Allegrini, P. W. Valek, David J. McComas, Jamey Szalay, and Robert Ebert
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Physics ,Jupiter ,Geophysics ,General Earth and Planetary Sciences ,Polar ,Astronomy ,Plasma ,Magnetosphere of Jupiter ,Ion - Published
- 2020
6. A New Framework to Explain Changes in Io's Footprint Tail Electron Fluxes
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John E. P. Connerney, Vincent Hue, Bertrand Bonfond, R. J. Wilson, Frederic Allegrini, Robert Ebert, Joachim Saur, Ali Sulaiman, George Clark, Jamey Szalay, Scott Bolton, David J. McComas, and Fran Bagenal
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Physics ,Footprint (electronics) ,Jupiter ,Geophysics ,General Earth and Planetary Sciences ,Electron ,Atmospheric sciences - Published
- 2020
7. First Report of Electron Measurements During a Europa Footprint Tail Crossing by Juno
- Author
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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)
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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
8. Juno In Situ Observations Above the Jovian Equatorial Ionosphere
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Robert Ebert, Jamey Szalay, Frederic Allegrini, John E. P. Connerney, Fran Bagenal, Robert J. Wilson, Scott Bolton, David J. McComas, and P. W. Valek
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In situ ,Physics ,Jupiter ,Geophysics ,General Earth and Planetary Sciences ,Ionosphere ,Jovian ,Astrobiology - Published
- 2020
9. Alfvénic Acceleration Sustains Ganymede's Footprint Tail Aurora
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Robert Ebert, Fran Bagenal, Masafumi Imai, Thomas K. Greathouse, G. R. Gladstone, Stavros Kotsiaros, Rohini Giles, R. J. Wilson, Ali Sulaiman, David J. McComas, George Hospodarsky, D. J. Gershman, William S. Kurth, Bertrand Bonfond, John E. P. Connerney, P. Louarn, Jamey Szalay, Joachim Saur, George Clark, Frederic Allegrini, and Scott Bolton
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Footprint (electronics) ,Physics ,Acceleration ,Geophysics ,General Earth and Planetary Sciences ,Astronomy ,JADE (particle detector) - Published
- 2020
10. Diverse Electron and Ion Acceleration Characteristics Observed Over Jupiter's Main Aurora
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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
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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
11. Energetic particle signatures of magnetic field-aligned potentials over Jupiter's polar regions
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Philip W Valek, George Clark, Steven Levin, Dennis Haggerty, Robert Ebert, Fran Bagenal, Chris Paranicas, Frederic Allegrini, Barry Mauk, William S. Kurth, Scott Bolton, John E. P. Connerney, G. Provan, Joachim Saur, Abigail Rymer, Emma J. Bunce, Stavros Kotsiaros, Stanley W. H. Cowley, Donald G. Mitchell, D. J. McComas, and Peter Kollmann
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Physics ,010504 meteorology & atmospheric sciences ,Magnetosphere ,Astronomy ,Electron ,01 natural sciences ,Magnetic field ,Jupiter ,Geophysics ,Planet ,Electric field ,Physics::Space Physics ,0103 physical sciences ,General Earth and Planetary Sciences ,Astrophysics::Earth and Planetary Astrophysics ,Electric potential ,Ionosphere ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
Recent results of the first ever orbit through Jupiter's auroral region by NASA's Juno spacecraft did not show evidence of coherent acceleration in the auroral or polar region. However, in this letter, we show energetic particle data from Juno's Jupiter Energetic-particle Detector Instrument instrument during the third auroral pass that exhibits conclusive evidence of downward parallel electric fields in portions of Jupiter's polar region. The energetic particle distributions show inverted-V ion and electron structures in a downward electric current region with accelerated peaked distributions in hundreds of keV to ~1 MeV range. The origin of these large electric potential structures is investigated and discussed within the current theoretical framework of current-voltage relationships at both Earth and Jupiter. Parallel electric fields responsible for accelerating particles to maintain the aurora/magnetospheric circuit appear to be a common phenomenon among strongly magnetized planets with conducting ionospheres; however, their origin and generation mechanisms are subjects of ongoing research.
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- 2017
12. Hot flow anomaly observed at Jupiter's bow shock
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C. J. Pollock, Fran Bagenal, Scott Bolton, S. Weidner, Michelle F. Thomsen, Barry Mauk, William S. Kurth, M. Reno, Steven Levin, R. J. Wilson, Philippe Louarn, John E. P. Connerney, Randy Gladstone, David J. McComas, Robert Ebert, Frederic Allegrini, Jamey Szalay, and Philip W Valek
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Physics ,010504 meteorology & atmospheric sciences ,biology ,Astronomy ,Magnetosphere ,Venus ,Mars Exploration Program ,biology.organism_classification ,01 natural sciences ,Jovian ,Current sheet ,Solar wind ,Geophysics ,Planet ,0103 physical sciences ,General Earth and Planetary Sciences ,Interplanetary spaceflight ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
A Hot Flow Anomaly (HFA) is created when an interplanetary current sheet interacts with a planetary bow shock. Previous studies have reported observing HFAs at Earth, Mercury, Venus, Mars and Saturn. During Juno's approach to Jupiter, a number of its instruments operated in the solar wind. Prior to crossing into Jupiter's magnetosphere, Juno observed an HFA at Jupiter for the first time. This Jovian HFA shares most of the characteristics of HFAs seen at other planets. The notable exception is that the Jovian HFA is significantly larger than any HFA seen before. With an apparent size greater than 2 × 106 km the Jovian HFA is orders of magnitude larger than those seen at the other planets. By comparing the size of the HFAs at the other planets with the Jovian HFA, we conclude that HFAs size scales with the size of planetary bow shocks that the interplanetary current sheet interacts with.
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- 2017
13. Response of Jupiter's auroras to conditions in the interplanetary medium as measured by the Hubble Space Telescope and Juno
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David J. McComas, Masaki Fujimoto, G. R. Gladstone, Jonathan D. Nichols, Bertrand Bonfond, Fran Bagenal, Chihiro Tao, Scott Bolton, Ichiro Yoshikawa, Robert Ebert, Sarah V. Badman, Go Murakami, Robert W. Wilson, A. Yamazaki, Stanley W. H. Cowley, Aikaterini Radioti, Barry Mauk, Emma J. Bunce, John E. P. Connerney, Jean-Claude Gérard, William S. Kurth, Tomoki Kimura, Phil Valek, Glenn S. Orton, Tom Stallard, John Clarke, and Denis Grodent
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Physics ,010504 meteorology & atmospheric sciences ,Astronomy ,Magnetosphere ,Interplanetary medium ,Noon ,01 natural sciences ,Jupiter ,Solar wind ,Geophysics ,Planet ,0103 physical sciences ,General Earth and Planetary Sciences ,Magnetopause ,Interplanetary spaceflight ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
We present the first comparison of Jupiter's auroral morphology with an extended, continuous and complete set of near-Jupiter interplanetary data, revealing the response of Jupiter's auroras to the interplanetary conditions. We show that for ∼1-3 days following compression region onset the planet's main emission brightened. A duskside poleward region also brightened during compressions, as well as during shallow rarefaction conditions at the start of the program. The power emitted from the noon active region did not exhibit dependence on any interplanetary parameter, though the morphology typically differed between rarefactions and compressions. The auroras equatorward of the main emission brightened over ∼10 days following an interval of increased volcanic activity on Io. These results show that the dependence of Jupiter's magnetosphere and auroras on the interplanetary conditions are more diverse than previously thought.
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- 2017
14. Juno observations of large-scale compressions of Jupiter's dawnside magnetopause
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Phil Valek, David J. McComas, Scott Bolton, Robert J. Wilson, George Hospodarsky, John E. P. Connerney, Daniel J. Gershman, Steve Levin, Robert Ebert, Fran Bagenal, Frederic Allegrini, Jamey Szalay, Gina A. DiBraccio, and William S. Kurth
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Physics ,010504 meteorology & atmospheric sciences ,Magnetosphere ,Magnetic reconnection ,Geophysics ,01 natural sciences ,Jupiter ,Solar wind ,Magnetosheath ,Magnetosphere of Saturn ,Physics::Space Physics ,0103 physical sciences ,General Earth and Planetary Sciences ,Magnetopause ,Magnetosphere of Jupiter ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
We investigate the structure of Jupiter's dawnside magnetopause using observations obtained by particle and fields instrumentation on the Juno spacecraft. Characterization of Jupiter's magnetopause is critical for the understanding of mass and energy transport between the solar wind and the magnetosphere. We find an extended magnetopause boundary layer (MPBL) during a magnetopause crossing on 14 July 2016. This thick MPBL, in combination with a large magnetic field component normal to the magnetopause boundary, suggests that strong magnetospheric compression enhances mass transport across the magnetopause via magnetic reconnection. We further identify ~2 h increases in the total magnetospheric pressure adjacent to the magnetopause on 14 July 2016 and 1 August 2016. These large-scale structures provide evidence of focused energy transport into the magnetosphere via magnetohydrodynamic structures.
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- 2017
15. Plasma measurements in the Jovian polar region with Juno/JADE
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John E. P. Connerney, Chris Paranicas, Steven Levin, D. J. Gershman, Michelle F. Thomsen, R. J. Wilson, M. Reno, Fran Bagenal, S. Weidner, David J. McComas, Barry Mauk, Robert Ebert, William S. Kurth, L. P. Dougherty, P. Louarn, Philip W Valek, D. A. Ranquist, Jamey Szalay, George Clark, Frederic Allegrini, and Scott Bolton
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Physics ,education.field_of_study ,010504 meteorology & atmospheric sciences ,Population ,Plasma sheet ,Astronomy ,Magnetosphere ,Torus ,Plasma ,01 natural sciences ,Jovian ,Jupiter ,Geophysics ,Physics::Plasma Physics ,Physics::Space Physics ,0103 physical sciences ,General Earth and Planetary Sciences ,Polar ,Astrophysics::Earth and Planetary Astrophysics ,education ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
Jupiter's main auroral oval provides a window into the complex magnetospheric dynamics of the jovian system. The Juno spacecraft entered orbit about Jupiter on 5 July 2016 and carries onboard the Auroral Distributions Experiment (JADE) that can directly sample the auroral plasma structures. Here, we identify five distinct regimes in the JADE data based on composition/energy boundaries and magnetic field mappings, which exhibit considerable symmetry between the northern and southern passes. These intervals correspond to periods when Juno was connected to the Io torus, inner plasma sheet, middle plasma sheet, outer plasma sheet, and the polar region. When connected to the torus and inner plasma sheet, the heavy ions are consistent with a corotating pickup population. For Juno's first perijove, we do not find evidence for a broad auroral acceleration region at Jupiter's main auroral oval for energies below 100 keV.
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- 2017
16. Plasma environment at the dawn flank of Jupiter's magnetosphere: Juno arrives at Jupiter
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Philip W Valek, David J. McComas, Scott Bolton, William S. Kurth, Jamey Szalay, M. Reno, S. Weidner, P. Louarn, Michelle F. Thomsen, John E. P. Connerney, Barry Mauk, R. J. Wilson, Fran Bagenal, Robert Ebert, and Frederic Allegrini
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Physics ,010504 meteorology & atmospheric sciences ,Astronomy ,Magnetosphere ,Plasma ,Bow shocks in astrophysics ,01 natural sciences ,JADE (particle detector) ,Jovian ,Jupiter ,Geophysics ,0103 physical sciences ,General Earth and Planetary Sciences ,Magnetopause ,Ionosphere ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
This study examines the first observations from the Jovian Auroral Distributions Experiment (JADE) as the Juno spacecraft arrived at Jupiter. JADE observations show that Juno crossed the bow shock at 08:16 UT on 2016 day of year (DOY) 176 and magnetopause at 21:20 on DOY 177, with additional magnetopause encounters until 23:39 on DOY 181. JADE made the first detailed observations of the plasma environment just inside the dawn flank of the magnetopause. We find subcorotational ions and variable electron beaming, with multiple flux tubes of varying plasma properties. Ion composition shows a dearth of heavy ions; protons dominate the plasma, with only intermittent, low fluxes of O+/S++, along with traces of O++ and S+++. We also find very little H3+ or He+, which are expected for an ionospheric plasma source. A few heavy ion bursts occur when the radial field nears reversal, but many other such reversals are not accompanied by heavy ions.
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- 2017
17. Generation of the Jovian hectometric radiation: First lessons from Juno
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Frederic Allegrini, P. Louarn, R. J. Wilson, N. André, J. L. Zink, William S. Kurth, Scott Bolton, John E. P. Connerney, Steven Levin, S. Weidner, Jamey Szalay, Robert Ebert, Masafumi Imai, David J. McComas, Philip W Valek, Fran Bagenal, 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)
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Physics ,010504 meteorology & atmospheric sciences ,Magnetosphere ,Astronomy ,Auroral kilometric radiation ,01 natural sciences ,Instability ,radio waves ,Jovian ,law.invention ,Jupiter ,Geophysics ,[SDU]Sciences of the Universe [physics] ,law ,Physics::Space Physics ,0103 physical sciences ,magnetosphere ,General Earth and Planetary Sciences ,Pitch angle ,Maser ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Radio wave - Abstract
International audience; Using Juno plasma and wave and magnetic observations (JADE and Waves and MAG instruments), the generation mechanism of the Jovian hectometric radio emission is analyzed. It is shown that suitable conditions for the cyclotron maser instability (CMI) are observed in the regions of the radio sources. Pronounced loss cone in the electron distributions are likely the source of free energy for the instability. The theory reveals that sufficient growth rates are obtained from the distribution functions that are measured by the JADE-Electron instrument. The CMI would be driven by upgoing electron populations at 5-10 keV and 10-30° pitch angle, the amplified waves propagating at 82°-87° from the B field, a fraction of a percent above the gyrofrequency. Typical e-folding times of 10-4 s are obtained, leading to an amplification path of 1000 km. Overall, this scenario for generation of the Jovian hectometric waves differs significantly from the case of the auroral kilometric radiation at Earth.
- Published
- 2017
18. Jovian bow shock and magnetopause encounters by the Juno spacecraft
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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
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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
19. Accelerated flows at Jupiter's magnetopause: Evidence for magnetic reconnection along the dawn flank
- Author
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M. Reno, Michelle F. Thomsen, Jamey Szalay, George Clark, Gina A. DiBraccio, P. Louarn, D. J. Gershman, D. J. McComas, Scott Bolton, Frederic Allegrini, S. Weidner, Steven Levin, Philip W Valek, William S. Kurth, Barry Mauk, Robert Ebert, John E. P. Connerney, R. J. Wilson, and Fran Bagenal
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Physics ,010504 meteorology & atmospheric sciences ,Magnetosphere ,Magnetic reconnection ,Geophysics ,Astrophysics ,01 natural sciences ,Jovian ,Jupiter ,Magnetosheath ,Magnetosphere of Saturn ,Physics::Space Physics ,0103 physical sciences ,General Earth and Planetary Sciences ,Magnetopause ,Astrophysics::Earth and Planetary Astrophysics ,Magnetosphere of Jupiter ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
We report on plasma and magnetic field observations from Juno's Jovian Auroral Distributions Experiment and Magnetic Field Investigation at eighteen magnetopause crossings when the spacecraft was located at ~6 h magnetic local time and 73 – 114 jovian radii from Jupiter. Several crossings showed evidence of plasma energization, accelerated ion flows, and large magnetic shear angles, each representing a signature of magnetic reconnection. These signatures were observed for times when the magnetosphere was in both compressed and expanded states. We compared the flow change magnitudes to a simplified Walen relation and found ~60% of the events to be 110% or less of the predicted values. Close examination of two magnetopause encounters revealed characteristics of a rotational discontinuity and an open magnetopause. These observations provide compelling evidence that magnetic reconnection can occur at Jupiter's dawn magnetopause and should be incorporated into theories of solar wind coupling and outer magnetosphere dynamics at Jupiter.
- Published
- 2017
20. Weaker solar wind from the polar coronal holes and the whole Sun
- Author
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David J. McComas, Bruce E. Goldstein, H. A. Elliott, J. T. Gosling, Robert Ebert, Nathan A. Schwadron, and Ruth M. Skoug
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Solar minimum ,Physics ,Astrophysics::High Energy Astrophysical Phenomena ,Coronal hole ,Astrophysics ,Coronal loop ,Geophysics ,Helmet streamer ,Corona ,Polar wind ,Physics::Space Physics ,Coronal mass ejection ,Astrophysics::Solar and Stellar Astrophysics ,General Earth and Planetary Sciences ,Astrophysics::Earth and Planetary Astrophysics ,Heliosphere - Abstract
[1] Observations of solar wind from both large polar coronal holes (PCHs) during Ulysses' third orbit showed that the fast solar wind was slightly slower, significantly less dense, cooler, and had less mass and momentum flux than during the previous solar minimum (first) orbit. In addition, while much more variable, measurements in the slower, in-ecliptic wind match quantitatively with Ulysses and show essentially identical trends. Thus, these combined observations indicate significant, long-term variations in solar wind output from the entire Sun. The significant, long-term trend to lower dynamic pressures means that the heliosphere has been shrinking and the heliopause must be moving inward toward the Voyager spacecraft. In addition, our observations suggest a significant and global reduction in the mass and energy fed in below the sonic point in the corona. The lower supply of mass and energy may result naturally from a reduction of open magnetic flux during this period.
- Published
- 2008
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