Rapid recovery of anomalous cosmic ray flux at 1 Au in solar cycle 22

Nobuyuki Hasebe*, Y. Mishima, K. Fujiki, M. Fujii, M. Kobayashi, T. Doke, J. Kikuchi, T. Hayashi, T. Shino, T. Ito, T. Takashima, T. Yanagimachi, A. Nakamoto, H. Murakami, K. Nagata, T. Kohno, K. Munakata, C. Kato, S. Yanagita, T. KashiwagiK. Maezawa, Y. Muraki, A. Nishida, T. Terasawa, B. Wilken

*Corresponding author for this work

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12 Citations (Scopus)


A new observation of low energy cosmic ray particles with the energies from 4 to 120 MeV/n by the HEP instrument onboard the GEOTAIL satellite orbiting at 1 AU shows a remarkable enhancement of anomalous cosmic ray (ACR) N, O and Ne in the period September 1992–December 1993 before approaching to the solar minimum in solar cycle 22. The ACR fluxes obtained by the GEOTAIL observation are in good agreement with the results earlier obtained from the SAMPEX satellite [Mewaldt et al. 1993a,b]. The ACR carbon is also evident though the C enhancement is small compared with those of N, O and Ne. We confirm the new SAMPEX finding that the ACR fluxes have recovered more rapidly in 1992–1993 than in previous solar cycles and find this tendency continues to the end of 1993.

Original languageEnglish
Pages (from-to)3027-3030
Number of pages4
JournalGeophysical Research Letters
Issue number25
Publication statusPublished - 1994
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)


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