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Solar wind response of the dawn-dusk asymmetry in the Io plasma torus using the Haleakala T60 and HISAKI satellite observations
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  • Hiroyasu Kondo,
  • Fuminori Tsuchiya,
  • Masato Kagitani,
  • Shinnosuke Satoh,
  • Hiroaki Misawa,
  • Yuki Nakamura,
  • Go Murakami,
  • Tomoki Kimura,
  • Atsushi Yamazaki,
  • Ichiro Yoshikawa,
  • Hajime Kita,
  • Chihiro Tao
Hiroyasu Kondo
Tohoku University
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Fuminori Tsuchiya
Tohoku University

Corresponding Author:[email protected]

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Masato Kagitani
Planetary Plasma and Atmospheric Research Center, Tohoku University
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Shinnosuke Satoh
Tohoku University
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Hiroaki Misawa
Graduate School of Science, Tohoku University
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Yuki Nakamura
Graduate School of Science, The University of Tokyo
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Go Murakami
Japan Aerospace Exploration Agency
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Tomoki Kimura
Tokyo University of Science
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Atsushi Yamazaki
Institute of Space and Astronautical Science
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Ichiro Yoshikawa
University of Tokyo
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Hajime Kita
Tohoku Institute of Technology
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Chihiro Tao
National Institute of Information and Communications Technology (NICT)
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Abstract

Plasma originating from the satellite Io forms a dense plasma region known as the Io plasma torus (IPT) in the Jovian inner magnetosphere. Slightly inside the Io-orbit is a distinct structure called the “ribbon,” where the plasma spreads along the magnetic field lines. The ribbon moved dawnward owing to the dawn-to-dusk electric field. Extreme ultraviolet (EUV) observations of the IPT showed that the electric field was enhanced under compressed conditions of the magnetosphere caused by solar wind. However, no reports have been published on the influence of solar wind on the radial position of the ribbon. Here, we show the correlation between the temporal variation in the ribbon’s position and solar wind. We analyzed the visible ([SII] 6716, 6731 Å) IPT images observed by the Tohoku 60-cm telescope (T60) and the EUV emissions observed by the Hisaki satellite. We found that the position of the ribbon shifted dawnward when the solar wind dynamic pressure was enhanced. The dawnward shift was more significant on the dawn side than on the dusk side, indicating that the change in the electric field was inhomogeneous. The simultaneous observations of T60 and the Hisaki satellite on February 19–23, 2016 indicated that the averaged intensity of the electric field derived from T60 was 3.9±0.9 mV/m, consistent with that of 2.8±1.2 mV/m derived from the Hisaki satellite. Our results demonstrate how solar wind affects the nonuniformity of the electric field in the inner magnetosphere.
19 May 2024Submitted to ESS Open Archive
28 May 2024Published in ESS Open Archive