Formation of the oxygen torus in the inner magnetosphere: Van Allen Probes observations

DOI Web Site Web Site Web Site Web Site ほか1件をすべて表示 一部だけ表示 被引用文献7件 参考文献38件
  • M. Nosé
    Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science Kyoto University Kyoto Japan
  • S. Oimatsu
    Department of Geophysics, Graduate School of Science Kyoto University Kyoto Japan
  • K. Keika
    Solar‐Terrestrial Environment Laboratory Nagoya University Nagoya Japan
  • C. A. Kletzing
    Department of Physics and Astronomy University of Iowa Iowa City Iowa USA
  • W. S. Kurth
    Department of Physics and Astronomy University of Iowa Iowa City Iowa USA
  • S. De Pascuale
    Department of Physics and Astronomy University of Iowa Iowa City Iowa USA
  • C. W. Smith
    Institute for Earth, Oceans and Space University of New Hampshire Durham New Hampshire USA
  • R. J. MacDowall
    Solar System Exploration Division Goddard Space Flight Center Greenbelt Maryland USA
  • S. Nakano
    Institute of Statistical Mathematics Research Organization of Information and Systems Tokyo Japan
  • G. D. Reeves
    Space Sciences and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA
  • H. E. Spence
    Institute for Earth, Oceans and Space University of New Hampshire Durham New Hampshire USA
  • B. A. Larsen
    Space Sciences and Applications Group Los Alamos National Laboratory Los Alamos New Mexico USA

書誌事項

公開日
2015-02
資源種別
journal article
権利情報
  • http://onlinelibrary.wiley.com/termsAndConditions#am
  • http://onlinelibrary.wiley.com/termsAndConditions#vor
DOI
  • 10.1002/2014ja020593
公開者
American Geophysical Union (AGU)

この論文をさがす

説明

<jats:title>Abstract</jats:title><jats:p>We study the formation process of an oxygen torus during the 12–15 November 2012 magnetic storm, using the magnetic field and plasma wave data obtained by Van Allen Probes. We estimate the local plasma mass density (<jats:italic>ρ</jats:italic><jats:sub>L</jats:sub>) and the local electron number density (<jats:italic>n</jats:italic><jats:sub><jats:italic>e</jats:italic>L</jats:sub>) from the resonant frequencies of standing Alfvén waves and the upper hybrid resonance band. The average ion mass (<jats:italic>M</jats:italic>) can be calculated by <jats:italic>M</jats:italic> ∼ <jats:italic>ρ</jats:italic><jats:sub>L</jats:sub>/<jats:italic>n</jats:italic><jats:sub><jats:italic>e</jats:italic>L</jats:sub> under the assumption of quasi‐neutrality of plasma. During the storm recovery phase, both Probe A and Probe B observe the oxygen torus at <jats:italic>L</jats:italic> = 3.0–4.0 and <jats:italic>L</jats:italic> = 3.7–4.5, respectively, on the morning side. The oxygen torus has <jats:italic>M</jats:italic> = 4.5–8 amu and extends around the plasmapause that is identified at <jats:italic>L</jats:italic>∼3.2–3.9. We find that during the initial phase, <jats:italic>M</jats:italic> is 4–7 amu throughout the plasma trough and remains at ∼1 amu in the plasmasphere, implying that ionospheric O<jats:sup>+</jats:sup> ions are supplied into the inner magnetosphere already in the initial phase of the magnetic storm. Numerical calculation under a decrease of the convection electric field reveals that some of thermal O<jats:sup>+</jats:sup> ions distributed throughout the plasma trough are trapped within the expanded plasmasphere, whereas some of them drift around the plasmapause on the dawnside. This creates the oxygen torus spreading near the plasmapause, which is consistent with the Van Allen Probes observations. We conclude that the oxygen torus identified in this study favors the formation scenario of supplying O<jats:sup>+</jats:sup> in the inner magnetosphere during the initial phase and subsequent drift during the recovery phase.</jats:p>

収録刊行物

被引用文献 (7)*注記

もっと見る

参考文献 (38)*注記

もっと見る

関連プロジェクト

もっと見る

キーワード

問題の指摘

ページトップへ