Effect of solar poloidal magnetic field reversal on diurnal anisotropy of cosmic ray intensity on quiet days

摘要

Using the Deep River neutron monitor (NM) data for the period 1964-95 covering three solar cycles, namely, 20,21 and 22, the long term trend and the effect of reversal of polarity of the solar magnetic field (PSMF) on the diurnal anisotropy of cosmic ray (CR) intensity on quiet days (QDs) have been investigated. The phase of the diurnal anisotropy on QD has started regaining its usual corotational direction after 1976, aquiring it in 1985 and remains statistically invariant till 1991. The phase of the diurnal anisotropy on QD has shown a significant shift to early hours when the PSMF in the northern hemisphere (NH) is positive during the periods 1971-79 and 1992-95 as compared to that during the periods 1964-70 and 1980-89 when the PSMF in the NH is negative, confirming again the earlier results of 22-yr periodicity.