Solar Magnetic Moment and Diurnal Variation in Cosmic-Ray Intensity

Abstract

The expected diurnal variation in cosmic-ray intensity at geomagnetic latitude 60° has been calculated assuming a solar magnetic dipole moment of 6.5×${10}^{33}$ gauss-${\mathrm{cm}}^3$. The calculation is based on new estimates of the intensity of cosmic radiation in the trapped orbits of the solar dipole field. The method of Dwight is followed, but with an important modification. The magnitude of the expected diurnal variation turns out to be about 12 percent.