Blar i forfatter "Yamauchi, Masatoshi"

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    • High-latitude crochet: Solar-flare-induced magnetic disturbance independent from low-latitude crochet 

      Yamauchi, Masatoshi; Johnsen, Magnar Gullikstad; Enell, Carl-Fredrik; Tjulin, Anders; Willer, Anna; Sormakov, Dmitry A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-03)
      A solar-flare-induced, high-latitude (peak at 70–75<sup>∘</sup> geographic latitude – GGlat) ionospheric current system was studied. Right after the X9.3 flare on 6 September 2017, magnetic stations at 68–77<sup>∘</sup> GGlat near local noon detected northward geomagnetic deviations (ΔB) for more than 3 h, with peak amplitudes of >200 nT without any accompanying substorm activities. From its location, ...

    • Plasma-neutral gas interactions in various space environments: Assessment beyond simplified approximations as a Voyage 2050 theme 

      Yamauchi, Masatoshi; De Keyser, Johan; Parks, George; Oyama, Shin-ichiro; Wurz, Peter; Abe, Takumi; Beth, Arnaud; Daglis, Ioannis A.; Dandouras, Iannis; Dunlop, Malcolm; Henri, Pierre; Ivchenko, Nickolay; Kallio, Esa; Kucharek, Harald; Liu, Yong C.-M.; Mann, Ingrid; Marghitu, Octav; Nicolaou, Georgios; Rong, Zhaojin; Sakanoi, Takeshi; Saur, Joachim; Shimoyama, Manabu; Taguchi, Satoshi; Tian, Feng; Tsuda, Takuo; Tsurutani, Bruce; Turner, Drew; Ulich, Thomas; Yau, Andrew; Yoshikawa, Ichiro (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-26)
      In the White Paper, submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we present the importance of advancing our knowledge of plasma-neutral gas interactions, and of deepening our understanding of the partially ionized environments that are ubiquitous in the upper atmospheres of planets and moons, and elsewhere in space. In future space missions, the above task ...

    • Solar illumination dependence of the auroral electrojet intensity: Interplay between the solar zenith angle and dipole tilt 

      Ohtani, Shinici; Gjerløv, Jesper; Johnsen, Magnar Gullikstad; Yamauchi, Masatoshi; Brändström, Urban; Lewis, Andrew M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-18)
      The present study investigates the dependence of the local auroral electrojet (AEJ) intensity on solar illumination by statistically examining northward geomagnetic disturbances in the auroral zone in terms of the solar zenith angle χ. It is found that on the dayside, both westward and eastward electrojets (WEJ and EEJ) are more intense for smaller χ, suggesting that the solar extreme ultraviolet‐induced ...