The intensity variation of cosmic rays associated with corotating interaction regions

K. Kondoh*, Nobuyuki Hasebe, T. Doke, J. Kikuchi, T. Takashima, M. N. Kobayashi, T. Yanagimachi, J. Medina, J. Sequeiros

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Long-term decrease events in the intensity of galactic cosmic rays have been investigated using solar wind parameters. We investigated distinct long-term decreases in 1993/94 near the solar minimum phase. In this period, the corotating interaction regions were observed over half a year. Recurrent increases of the solar wind speed were observed during this time period, forming corotating interaction regions. Simultaneously recurrent energetic proton events and recurrent decrease of galactic cosmic rays are measured. The baseline counts of neutron monitors was well anti-correlated with the peak speed of solar wind. It is suggested that long-lasting enhancements of solar wind velocity or corotating interaction regions formed by them can produce the long-term decrease in the galactic cosmic ray intensity.

Original languageEnglish
Pages (from-to)591-594
Number of pages4
JournalAdvances in Space Research
Issue number3
Publication statusPublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics


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