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Yoshioka K, Murakami G, Yamazaki A, Tsuchiya F, Kimura T, Kagitani M, Sakanoi T, Uemizu K, Kasaba Y, Yoshikawa I, Fujimoto M. Evidence for global electron transportation into the jovian inner magnetosphere. Science 2014; 345:1581-4. [PMID: 25258073 DOI: 10.1126/science.1256259] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Jupiter's magnetosphere is a strong particle accelerator that contains ultrarelativistic electrons in its inner part. They are thought to be accelerated by whistler-mode waves excited by anisotropic hot electrons (>10 kiloelectron volts) injected from the outer magnetosphere. However, electron transportation in the inner magnetosphere is not well understood. By analyzing the extreme ultraviolet line emission from the inner magnetosphere, we show evidence for global inward transport of flux tubes containing hot plasma. High-spectral-resolution scanning observations of the Io plasma torus in the inner magnetosphere enable us to generate radial profiles of the hot electron fraction. It gradually decreases with decreasing radial distance, despite the short collisional time scale that should thermalize them rapidly. This indicates a fast and continuous resupply of hot electrons responsible for exciting the whistler-mode waves.
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Affiliation(s)
- K Yoshioka
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan.
| | - G Murakami
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan
| | - A Yamazaki
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan
| | - F Tsuchiya
- Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Japan
| | - T Kimura
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan
| | - M Kagitani
- Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Japan
| | - T Sakanoi
- Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Japan
| | - K Uemizu
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan. National Astronomical Observatory of Japan, Mitaka, Japan
| | - Y Kasaba
- Department of Geophysics, Tohoku University, Sendai, Japan
| | - I Yoshikawa
- Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan
| | - M Fujimoto
- Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Japan. Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
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Dols V, Delamere PA, Bagenal F, Kurth WS, Paterson WR. Asymmetry of Io's outer atmosphere: Constraints from five Galileo flybys. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012je004076] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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3
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Bagenal F, Delamere PA. Flow of mass and energy in the magnetospheres of Jupiter and Saturn. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010ja016294] [Citation(s) in RCA: 222] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fran Bagenal
- Laboratory for Atmospheric and Space Physics; University of Colorado at Boulder; Boulder Colorado USA
| | - Peter A. Delamere
- Laboratory for Atmospheric and Space Physics; University of Colorado at Boulder; Boulder Colorado USA
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Fleshman BL, Delamere PA, Bagenal F. A sensitivity study of the Enceladus torus. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003372] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mauk BH. Energetic ion characteristics and neutral gas interactions in Jupiter's magnetosphere. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003ja010270] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Delamere PA. Modeling temporal variability of plasma conditions in the Io torus during the Cassini era. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003ja010354] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mauk BH, Mitchell DG, Krimigis SM, Roelof EC, Paranicas CP. Energetic neutral atoms from a trans-Europa gas torus at Jupiter. Nature 2003; 421:920-2. [PMID: 12606993 DOI: 10.1038/nature01431] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2002] [Accepted: 01/13/2003] [Indexed: 11/09/2022]
Abstract
The space environments--or magnetospheres--of magnetized planets emit copious quantities of energetic neutral atoms (ENAs) at energies between tens of electron volts to hundreds of kiloelectron volts (keV). These energetic atoms result from charge exchange between magnetically trapped energetic ions and cold neutral atoms, and they carry significant amounts of energy and mass from the magnetospheres. Imaging their distribution allows us to investigate the structure of planetary magnetospheres. Here we report the analysis of 50-80 keV ENA images of Jupiter's magnetosphere, where two distinct emission regions dominate: the upper atmosphere of Jupiter itself, and a torus of emission residing just outside the orbit of Jupiter's satellite Europa. The trans-Europa component shows that, unexpectedly, Europa generates a gas cloud comparable in gas content to that associated with the volcanic moon Io. The quantity of gas found indicates that Europa has a much greater impact than hitherto believed on the structure of, and the energy flow within, Jupiter's magnetosphere.
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Affiliation(s)
- B H Mauk
- The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland 20723, USA.
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Cravens TE. Implications of Jovian X-ray emission for magnetosphere-ionosphere coupling. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2003ja010050] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Crary FJ, Bagenal F. Ion cyclotron waves, pickup ions, and Io's neutral exosphere. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/2000ja000055] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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