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The study of the precursory decrease of cosmic rays before the Forbush decrease.

Research Project

Project/Area Number 09640531
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Space and upper atmospheric physics
Research InstitutionNagoya University

Principal Investigator

FUJIMOTO Kazuhiko  Solar-Terrestrial Environment Laboratory, Nagoya University, Assistant, 太陽地球環境研究所, 助手 (10022617)

Co-Investigator(Kenkyū-buntansha) MORISHITA Isao  Department of Information Management, Asahi University, Professor, 経営学部, 教授 (40148200)
JUJII Zenjiro  Solar-Terrestrial Environment Laboratory, Nagoya University, Assistant, 太陽地球環境研究所, 助手 (10022724)
YASUNO Shizuko  Solar-Terrestrial Environment Laboratory, Nagoya University, Assistant Professor, 太陽地球環境研究所, 助教授 (30022586)
Project Period (FY) 1997 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1998: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1997: ¥1,600,000 (Direct Cost: ¥1,600,000)
KeywordsCosmic ray / Solar Magnetic Cloud / Forbush decrease / Precusory event
Research Abstract

The existence of the precursory decrease of cosmic rays in front of the shock wave of the interplanetary magnetic field (IMF) was pointed out by Fujimoto et al. and the phenomenon has been interpreted as being due to their IMF-collimated outward flow across the shock from the inside of the Forbush decrease.
To observe such a beam-like precursory decrease effectively, a new narrow angle multidirectional muon telescope have been constructed at Mt. Norikura and fully operated since May 1998. The telescope covers *50゚ of the sky with the angular resolution of about 7゚ Forbush decrease events were observed on 26 August and 25 September in 1998. The counting rates of the event are plotted in the two-dimensional map of 21*21 bin. The time sequence of the plot seems to indicate that the F.D.event is not uniform in space and is non-stable in time. We submit the report of the above results to 26th Int. Cosmic ray Conference, Salt Lake City, in August 1999.

Report

(3 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] K.Fujimoto.: "Mean free path of cosmic rays in the disturbance region behind IMF-shock,causing Forbush decrease at September 9,1992." Proc.25th Int.Cosmic Ray Conf.Durban. 1. 433-436 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Y.Ohashi: "New Narrow angle muon telescope at Mt.Norikura." Proc.25th Int.Cosmic Ray Conf.Durban. 1. 441-444 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] I.Morishita: "Characteristics of precursory decrease of Forbush decrease inferred from world wide ob servations of muon and neutron intensities." Proc.25th Int.Cosmic Ray Conf.,Durban. 1. 405-408 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Munakata: "Long term variation of cosmic-ray diurnal anisotropy observed by a network of muon telescope in a wide range of rigidity." Proc.25th Int.Cosmic Ray Conf.,Durban. 2. 77-80 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Nagashima: "Galactic and heliotail-in anisotropies of cosmic rays as the origin of sidereal daily variation in the energy region less than 10^4GeV." J.Geophysic.Res.103. 17,429-17,440 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Fujimoto, Z.Fujii, K.Munakata, S.Yasue, I.Mor-ishita, J.E.Humble, A.G.Fenton, K.B.Fenton and M.L.Duldig: "Mean free path of cosmic rays in the disturbance region behind IMF-shock, causing Forbush decrease at Septem-ber, 9,1992." Proc.25th Int.Cosmic Ray Con-f., Durban. 1. 433-436 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] Y.Ohashi, A.Okada, T.Aoki, K.Mitsui, H.Kojima and K.Fujimoto: "New Narrow angle muon telescope at Mt.Norikura." Proc.25th Int.Cosmic Ray Con-f., Durban. 1. 441-444 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] I.Morishita, K.Fujimoto, Z.Fujii, S.Sakakibara, K.Nagashima, K.Munakata, S.Yasue, J.E.Humble, K.B.Fenton, A.G.Fenton and M.L.Duldig: "Characteristics of precursory decrease of Forbush de-crease inferred from world wide observations of muon and neutron intensities." Proc.25th Int.Cosmic Ray Con-f., Durban. 1. 405-408 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Munakata, H.Miyasaka, D.L.Hall, S.Yasue, C.Kato, Z.Fujii, K.Fujimoto and S.Sakakibara: "Long term variation of cosmic-ray diurnal anisotropy ob-served by a network of multi-directional muon telescope in a wide range of rigidity." Proc.25th Int.Cosmic Ray Con-f., Durban. 2. 77-80 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Nagashima, K.Fujimoto and R.M.Jacklyn: "Galactic and heliotail-in anisotropies of cosmic rays as the origin of sidereal daily variation in the energy region less than 10^4GeV." J.Geophysic.Res.103, NO.A8. 17,429-17,440 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] K.Fujimoto: "Mean free path of cosmic rays in the disturbance region behind IMF-shock, causing Forbush decrease at Steptember 9, 1992." Proc.25th Int.Cosmic Ray Conf.Durban. 1. 433-436 (1997)

    • Related Report
      1998 Annual Research Report
  • [Publications] Y.Ohashi: "New Narrow angle muon telescope at Mt.Norikura." Proc.25th Int.Cosmic Ray Conf.Durban. 1. 441-444 (1997)

    • Related Report
      1998 Annual Research Report
  • [Publications] I.Morishita: "Characteristics of precursory decrease of Forbush decrease inferred from world wide ob servations of muon and neutron intensities." Proc.25th Int.Cosmic Ray Conf.Durban. 1. 405-408 (1997)

    • Related Report
      1998 Annual Research Report
  • [Publications] K.Munakata: "Long term variation of cosmic-ray diurnal anisotropy observed by a network of muon telescope in a wide range of rigidity." Proc.25th Int.Cosmic Ray Conf.Durban. 2. 77-80 (1997)

    • Related Report
      1998 Annual Research Report
  • [Publications] K.Nagashima: "Galactic and heliotail-in anisotropies of cosmic rays as the origin of sidereal daily variation in the energy region less than 10^4GeV." J.Geophysic.Res.103. 17,429-17,440 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] K.Fujimoto: "Mean free path of cosmic rays in the disturbance region behind IMF-shock,causing Forbush decrease at September 9,1992." Proc.25th Int.Cosmic Ray Conf.Durban. 1. 433-436 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] Y.Ohashi: "New Narrow angle muon telescope at Mt.Norikura." Proc.25th Int.Cosmic Ray Conf.Durban. 1. 441-444 (1997)

    • Related Report
      1997 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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