Propagation of solar corpuscles and interplanetary magnetic fields

Abstract

A model of interplanetary magnetic fields formed by the outward blast of solar plasma clouds can account for various characteristics of solar particles observed on the earth. All available information on solar-geophysical data has been examined, including flares, solar radio emissions, polar-cap absorptions, and geomagnetic and cosmic-ray storms for the period from July 1957 to December 1960. It is shown that a plasma cloud ejected from the sun forms an expanding magnetic bulge that is linked with the sun and can trap or sweep out solar cosmic rays, depending on the relative positions of the injected particles and of the cloud in space. The results also confirm some inequality of the time variations of solar cosmic-ray flux with respect to the heliographic position of the source flares. This is explained by the westward convex nature of magnetic field lines due to the rotation of the sun. The average speed and the lifetime of magnetic plasma clouds are estimated from the characteristics of delay times between solar flares and geomagnetic storms.