Short-term variation of cosmic ray diurnal anisotropy and solar activity

A correlative analysis has been made between cosmic ray intensity and solar activity (sunspot numbers) during high amplitude days for the period 1991–1995. The high amplitude days with the time of maximum in the corotational/azimuthal direction do not indicate any significant correlation with solar activity. The diurnal amplitude significantly remains constant and high (0.5%) during the entire period. Our observations suggest that the direction of the anisotropy of high amplitude anisotropic wave train events contribute significantly to the short-term behavior of the cosmic ray diurnal anisotropy. The correlation coefficient is found to remain positive during solar activity maximum for all the high amplitude anisotropic wave train events.