The role of drift on the diurnal anisotropy and on temporal changes in the energy spectra of the 11-year variation for galactic cosmic rays

• Published in: Advances in space research Vol. 27; no. 3; pp. 613 - 618
• Main Authors: Alania, M V, Aslamazashvili, R G, Bochorishvili, T B, Iskra, K, Siluszyk, M
• Format: Journal Article
• Language: English
• Published: 01.07.2000
• ISSN: 0273-1177

Neutron monitor and IMF data are used to study features of the role of drift effect in the temporal changes of the diurnal anisotropy and of the energy spectrum of the 11-yr variation of galactic cosmic rays. In order to strictly separate the sectors of the IMF and its influence on the anisotropy of galactic cosmic rays, four solar minima periods (1965, 1976, 1987 and 1997) are considered. An attempt is made to separate drift effects in the diurnal anisotropy of galactic cosmic rays, first, due to the gradient and curvature of the regular IMF, and second, due to the heliospheric neutral sheet. The global survey method is used to calculate the components of the 3D diurnal anisotropy of galactic cosmic rays based on neutron monitor data. It is shown that there are significant differences between the diurnal anisotropy of galactic cosmic rays found in the reliably established various sectors (duration of each sectors is > 4 d) of the IMF. The IMF sector structure effect in the diurnal anisotropy of galactic cosmic rays is assumed to be connected to the heliospheric neutral sheet drift, while 22-year variation of the diurnal anisotropy of galactic cosmic rays is assumed to be connected to drift due to the gradient and curvature of the regular IMF for different qA > 0 and qA < 0 solar magnetic cycles. It is shown that the role of drift in the temporal changes of the energy spectrum of the 11-year variation of GCR is insignificant in both of the qA > 0 and the qA < 0 solar magnetic cycles. (Author)