Experimental and theoretical investigations of the 11-year variation of galactic cosmic rays Original Research Article

Data of super neutron monitors have been used to study features of the temporal changes of the energy spectrum of the galactic cosmic rays isotropic intensity variations in the various ascending and descending epochs of solar activity (1954–2000) for different solar magnetic cycles (qA > 0 and the qA < 0). Parkerʹs transport equation is numerically solved in order to establish a relationship between the experimentally obtained and theoretically expected energy spectra of.galactic cosmic rays. It is found that the theoretical expected energy spectrum is single valued determined by the dependence of the diffusion coefficient on the rigidity of galactic cosmic rays. The temporal changes of the energy spectrum of galactic cosmic rays isotropic intensity variations from the maxima to the minima epochs of solar activity indicate the radical redistributions of the EAFʹs fluctuations (irregularities) from the higher frequencies to the lower frequencies. It is concluded that this radical redistributions of the DVIFʹs fluctuations from the maxima to the minima epochs is one of the general reasons (mechanism) of the 11-year variation of the galactic cosmic rays m 2003 COSPAR.