Study of High/Low Amplitude Wave Trains in CR Intensity and Associated Solar Features

Cosmic Ray intensity data for a period of over a decade (i.e., 1989-1990) from various neutron-monitoring stations; situated at different latitudes, have been investigated for the high/low amplitude anisotropic wave train events (HAE/LAE). It has been found that the diurnal phase of cosmic ray anisotropy appears to be indep endent of amplitude, as no synchronization in variations is seen between them for ma jority of the HAE/LAE cases. However, the phase of the semi-diurnal anisotropy for HAE has been found to shift towards later hours for all the events. The geomagnetic activity index Ap has been observed to remain low during the period of each HAE/LAE. The possible phenomenon to cause such high/low amplitude anisotropic wave trains has been proposed to appear on the back of the visible side of the Sun.