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

M. Nosé, A. Matsuoka, A. Kumamoto, Y. Kasahara, J. Goldstein, M. Teramoto, F. Tsuchiya, S. Matsuda, M. Shoji, S. Imajo, S. Oimatsu, K. Yamamoto, Y. Obana, R. Nomura, A. Fujimoto, I. Shinohara, Y. Miyoshi, W. S. Kurth, C. A. Kletzing, C. W. SmithR. J. MacDowall

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Simultaneous 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.

Original languageEnglish
Pages (from-to)10,177-10,184
JournalGeophysical Research Letters
Volume45
Issue number19
DOIs
Publication statusPublished - 2018 Oct 16

Keywords

  • Arase satellite
  • Van Allen Probes satellite
  • geomagnetic storm
  • inner magnetosphere
  • oxygen torus
  • simultaneous observation

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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