Statistical Study of Selective Oxygen Increase in High-Energy Ring Current Ions During Magnetic Storms

K. Mitani, K. Seki, K. Keika, M. Gkioulidou, L. J. Lanzerotti, D. G. Mitchell, C. A. Kletzing, Akimasa Yoshikawa, Y. Obana

Research output: Contribution to journalArticle

Abstract

Ion transport from the plasma sheet to the ring current is the main cause of the development of the ring current. Energetic (>150 keV) ring current ions are known to be transported diffusively in several days. A recent study suggested that energetic oxygen ions are transported closer to the Earth than protons due to the diffusive transport caused by a combination of the drift and drift-bounce resonances with Pc 3–5 ultralow frequency waves during the 24 April 2013 magnetic storm. To understand the occurrence conditions of such selective oxygen increase (SOI), we investigate the phase space densities (PSDs) between protons and oxygen ions with the first adiabatic invariants (μ) of 0.1–2.0 keV/nT measured by the Radiation Belt Storm Probes Ion Composition Experiment instrument on the Van Allen Probes at L ~ 3–6 during 90 magnetic storms in 2013–2017. We identified the SOI events in which oxygen PSDs increase while proton PSDs do not increase during a period of ~9 hr (one orbital period). Among the 90 magnetic storms, 33% were accompanied by the SOI events. Global enhancements of Pc 4 and Pc 5 waves observed by ground magnetometers during the SOI events suggest that radial transport due to combination of the drift-bounce resonance with Pc 4 oscillations and the drift resonance with Pc 5 oscillations can be the cause of SOIs. The contribution of the SOI events to the magnetic storm intensity is roughly estimated to be ~9% on average.

Original languageEnglish
Pages (from-to)3193-3209
Number of pages17
JournalJournal of Geophysical Research: Space Physics
Volume124
Issue number5
DOIs
Publication statusPublished - May 1 2019

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ring currents
current ring
magnetic storms
Ions
ions
Oxygen
oxygen
space density
ion
energy
protons
oxygen ions
Protons
ion probes
oscillation
extremely low frequencies
radiation belts
oscillations
energetics
causes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Cite this

Mitani, K., Seki, K., Keika, K., Gkioulidou, M., Lanzerotti, L. J., Mitchell, D. G., ... Obana, Y. (2019). Statistical Study of Selective Oxygen Increase in High-Energy Ring Current Ions During Magnetic Storms. Journal of Geophysical Research: Space Physics, 124(5), 3193-3209. https://doi.org/10.1029/2018JA026168

Statistical Study of Selective Oxygen Increase in High-Energy Ring Current Ions During Magnetic Storms. / Mitani, K.; Seki, K.; Keika, K.; Gkioulidou, M.; Lanzerotti, L. J.; Mitchell, D. G.; Kletzing, C. A.; Yoshikawa, Akimasa; Obana, Y.

In: Journal of Geophysical Research: Space Physics, Vol. 124, No. 5, 01.05.2019, p. 3193-3209.

Research output: Contribution to journalArticle

Mitani, K, Seki, K, Keika, K, Gkioulidou, M, Lanzerotti, LJ, Mitchell, DG, Kletzing, CA, Yoshikawa, A & Obana, Y 2019, 'Statistical Study of Selective Oxygen Increase in High-Energy Ring Current Ions During Magnetic Storms', Journal of Geophysical Research: Space Physics, vol. 124, no. 5, pp. 3193-3209. https://doi.org/10.1029/2018JA026168
Mitani, K. ; Seki, K. ; Keika, K. ; Gkioulidou, M. ; Lanzerotti, L. J. ; Mitchell, D. G. ; Kletzing, C. A. ; Yoshikawa, Akimasa ; Obana, Y. / Statistical Study of Selective Oxygen Increase in High-Energy Ring Current Ions During Magnetic Storms. In: Journal of Geophysical Research: Space Physics. 2019 ; Vol. 124, No. 5. pp. 3193-3209.
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