Modulation of Heavy Nuclei in the Primary Cosmic Radiation

Abstract

The intensities of the primary cosmic-ray heavy nuclei, $Z>~3$, have been studied during several Forbush decreases. Fifteen values of the intensity were measured using nuclear emulsion detectors flown during a balloon cosmic-ray monitoring program. These values are those observed before, during, or after four of the largest Forbush decreases that occurred in the last solar cycle. Examination of these data, together with those previously available in the literature, suggests that the heavy nuclei are modulated in a similar manner to the $\ensuremath{\alpha}$ particles and protons of the primary radiation, showing that the modulation process is not a strongly charge-dependent one.