Effect of Interplanetary Transients on Cosmic Ray Anisotropic Variations

In the present work the cosmic ray intensity data recorded with ground-based neutron monitor at Deep River has investigated taking into account the associated interplanetary magnetic field and solar wind plasma data during 1981-1994. A large number of days having abnormally high/low amplitudes for successive number of five or more days as compared to annual average amplitude of diurnal anisotropy have been taken as high/low amplitude anisotropic wave train events (HAE/LAE). The amplitude of the diurnal anisotropy of these events is found to increase on the days of magnetic cloud as compared to the days prior to the event and it found to decrease during the later period of the event as the cloud passes the Earth. The High-Speed Solar Wind Streams (HSSWS) do not play any significant role in causing these types of events. The interplanetary disturbances (magnetic clouds) are also effective in producing cosmic ray decreases. Hα solar flares have a good positive correlation with both amplitude and direction of the anisotropy for HAEs,whereas PMSs have a good positive correlation with both amplitude and direction of the anisotropy for LAEs.The source responsible for these unusual anisotropic wave trains in CR has been proposed.