Rapid Reduction of Cosmic-Radiation Intensity Measured in Interplanetary Space

Results of studies of variation in cosmic-ray intensity at the earth and at the position of Pioneer V in interplanetary space proved that the rapid reduction in galactic cosmic radiation is a phenomenon of solar origin, taking place in interplanetary space, and is not related to the presence of the earth or its magnetic field. Since the observed intensity decreases only follow solar flares on the visible side of the sun, the reduction of cosmic-particle intensity is confined to a limited volume of the inner solar system. Properties of the modulating magnetic fields were also determined. (M.C.G.)