Solar Magnetic Moment and Cosmic-Ray Effects Associated with Solar Flares

Abstract

A close correlation between solar flares and small cosmic-ray intensity increases has recently been established by the Climax, Colorado, neutron monitor data. The correlation, however, is restricted only to those flares which occur when the station lies within a certain interval of local solar time. This has been explained by supposing that the new cosmic-ray particles approach the earth preferentially along the earth-sun line, before deflection in the terrestrial magnetic field takes place. In the present paper, this evidence is used to establish an upper limit to a possible solar magnetic dipole field. Allowance is made for the fact that the dipole field may be seriously perturbed by local fields near the sun; but on the assumption that the dipole field predominates far from the sun (at distances greater than one-fifth the earth-sun distance), the upper limit on the solar dipole moment is 5×${10}^{32}$ gauss-${\mathrm{cm}}^3$.