AKR disappearance during magnetic storms

A. Morioka, Y. Miyoshi, T. Seki, Fuminori Tsuchiya, Hiroaki Misawa, H. Oya, H. Matsumoto, K. Hashimoto, T. Mukai, K. Yumoto, T. Nagatsuma

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11 Citations (Scopus)


It is well known that auroral kilometric radiation (AKR) is intensified during substorms and has a good correlation with AE index. In the case of the magnetic storms, however, AKR characteristics have not been investigated. In this paper we report unexpected behavior of the storm-time AKR and its related particle precipitation: (1) AKR often disappears in the initial and main phases of the magnetic storms in spite of the large enhancement of AE index and field-aligned current; (2) At that time, the energy spectra of precipitating electrons do not show signature of the field-aligned acceleration but hot electron injection; (3) The radiation activates strongly in the recovery phase; and (4) AKR tends to disappear in larger storms. These results suggest that the field-aligned electric field which accelerates precipitating electrons and drives field-aligned currents is not formed in the initial and main phases of magnetic storms.

Original languageEnglish
Article number1226
JournalJournal of Geophysical Research: Space Physics
Issue numberA6
Publication statusPublished - 2003 Jan 1


  • AKR
  • Auroral acceleration
  • Magnetic storm
  • Substorm

ASJC Scopus subject areas

  • 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

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    Morioka, A., Miyoshi, Y., Seki, T., Tsuchiya, F., Misawa, H., Oya, H., Matsumoto, H., Hashimoto, K., Mukai, T., Yumoto, K., & Nagatsuma, T. (2003). AKR disappearance during magnetic storms. Journal of Geophysical Research: Space Physics, 108(A6), [1226]. https://doi.org/10.1029/2002JA009796