Direction of the cosmic ray anisotropy

Abstract

Inclined meson telescopes at Uppsala, Kiruna, and Murchison Bay have been employed to determine the direction of the C.R. diurnal anisotropy. The six mean asymptotic directions are distributed between approximately 15° N and 80° N. It is being shown that the flow of excess particles responsible for the anisotropy is parallel to the orbital plane of the earth. All atmospheric effects have been considered as well as the partial smoothing out of the diurnal variation through the longitudinal distribution of the asymptotic directions. Inside the limits of error the yearly mean amplitudes fit a linear function of the cosine of the angle between the equatorial plane and the mean asymptotic direction. The direction of the anisotropy makes an angle of approximately 90° with the earth-sun line, the flow of excess particles overtaking the earth.