Longitudinal Structure of Oxygen Torus in the Inner Magnetosphere: Simultaneous Observations by Arase and Van Allen Probe A

TitleLongitudinal Structure of Oxygen Torus in the Inner Magnetosphere: Simultaneous Observations by Arase and Van Allen Probe A
Publication TypeJournal Article
Year of Publication2018
Authorsé, M, Matsuoka, A, Kumamoto, A, Kasahara, Y, Goldstein, J, Teramoto, M, Tsuchiya, F, Matsuda, S, Shoji, M, Imajo, S, Oimatsu, S, Yamamoto, K, Obana, Y, Nomura, R, Fujimoto, A, Shinohara, I, Miyoshi, Y, Kurth, WS, Kletzing, CA, Smith, CW, MacDowall, RJ
JournalGeophysical Research Letters
Pagination10,177 - 10,184
Date Published10/2018
KeywordsArase satellite; Geomagnetic storm; inner magnetosphere; oxygen torus; simultaneous observation; Van Allen Probes; Van Allen Probes satellite
AbstractSimultaneous observations of the magnetic field and plasma waves made by the Arase and Van Allen Probe A satellites at different magnetic local time (MLT) enable us to deduce the longitudinal structure of an oxygen torus for the first time. During 04:00–07:10 UT on 24 April 2017, Arase flew from L = 6.2 to 2.0 in the morning sector and detected an enhancement of the average plasma mass up to ~3.5 amu around L = 4.9–5.2 and MLT = 5.0 hr, implying that the plasma consists of approximately 15% O+ ions. Probe A moved outbound from L = 2.0 to 6.2 in the afternoon sector during 04:10–07:30 UT and observed no clear enhancements in the average plasma mass. For this event, the O+ density enhancement in the inner magnetosphere (i.e., oxygen torus) does not extend over all MLT but is skewed toward the dawn, being described more precisely as a crescent‐shaped torus or a pinched torus.
URLhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL080122
DOI10.1029/2018GL080122
Short TitleGeophys. Res. Lett.


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