Earth, Moon, and Planets

, Volume 37, Issue 1, pp 79–88 | Cite as

An empirical model for the 11-year cosmic-ray modulation

  • H. Mavromichalaki
  • B. Petropoulos


An analysis of monthly data from nine world-wide neutron monitoring stations over the period 1965–1975 is carried out for the study of the long-term cosmic-ray modulation. In an attempt to gain insight into the relationships which exist between solar activity, high-speed solar wind streams and various terrestrial phenomena an empirical relation for the cosmic-ray modulation has been found. Accordingly the modulated cosmic-ray intensity is equal to the galactic cosmic-ray intensity corrected by a few appropriate solar, interplanetary and terrestrial activity indices which causes the disturbances in interplanetary space, multiplying with the corresponding time-lag of cosmic-ray intensity from each of these indices. This relation is well explained by a generalization of the Simpson solar wind model which has been proved by the spherically symmetric diffusion-convection theory.


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Copyright information

© D. Reidel Publishing Company 1987

Authors and Affiliations

  • H. Mavromichalaki
    • 1
  • B. Petropoulos
    • 2
  1. 1.Physics Department, Nuclear and Particle Physics SectionUniversity of AthensGreece
  2. 2.Research Centre for Astronomy and Applied Mathematics, Academy of AthensGreece

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