Cosmic Ray Density Gradients Perpendicular to the Solar Equatorial Plane

Abstract

The existence of cosmic ray semi-diurnal anisotropy of interplanetary origin has generally been attributed to the symmetrically rising density gradients perpendicular to the solar equatorial plane. A factor of 2 for the increase in the magnitude of semi-diurnal anisotropy of cosmic rays during 1973-75 is theoretically expected to be associated with larger magnitude of the heliolatitudinal density gradients. The distribution of cosmic ray intensity in the heliolatitude range ±7.25° obtained using the data of Deep River neutron mintitor does not support the density gradient hypothesis. However, the presence of symmetrical gradients at higher heliolatitudes cannot be ruled out.