Supernova Origin of Cosmic Rays

Abstract

The supernova origin of cosmic rays is proposed in connection with the stellar evolution and the building up of heavy elements in the core of stars as they evolve. Nearly equal abundances of heavy and medium nuclei in primary cosmic rays suggest that the sources may be such stars, in which the thermonuclear reactions of building up heavy elements take place and which eventually explode as supernovae. The light elements, Li, Be and B, in galactic matter are considered to be generated by the nuclear bombardment of heavier nuclei at the explosion. The number of cosmic ray particles injected there is estimated in reference to the radio emission of supernova remnants. If the number injected is of the order of 1051 per supernova and the explosion is more frequent than now observed, the supernova origin is shown to be not inconsistent with cosmic ray as well as astronomical evidences. The galactic model suitable to our interpretation is a sphere with magnetic clouds. The life time of cosmic rays in this galaxy is estimated to be of the order of 108 years, corresponding to the fact that the mean thickness of interstellar matter traversed by cosmic rays is about 1 g cm-2, that is, estimated from the abundance of the light nuclei in the primary cosmic rays.