Very Heavy Nuclei in the Primary Cosmic Radiation. II. Interpretation of the Energy Spectra

Abstract

An attempt has been made to understand the form of the observed energy spectrum of the highly charged ($20\le Z\le 30$) nuclei in the primary cosmic radiation. It is shown that the behavior of this spectrum relative to that of the helium nuclei also present in the cosmic radiation can be explained by assuming that the highly charged nuclei have two components. The first of these components is dominant at high energies and has a spectrum at the source that can be represented as a simple power law with a slope somewhat flatter than that of the source spectrum of the helium nuclei. The nuclei in this component may be regarded as having traversed several g/${\mathrm{cm}}^2$ of matter between the times of acceleration and of detection. The second component is of importance only at relatively low energies (a few hundred MeV/nucleon), has a spectrum that falls steeply with increasing energy, and cannot simply be represented as a power law. The possible consequences of such a model are briefly considered.