Pulsar-produced cosmic rays and the origin of the light elements

Particles accelerated in the vicinity of pulsars must traverse the expanding shell of the supernova before emerging as cosmic rays. This passage results in a considerable intensity reduction and in the production of light nuclei by fragmentation of heavy nuclei of the shell gas. It is shown that the upper limit of the pulsar contribution to the cosmic-ray flux is of the order of a few percent or less of the total galactic production, but that even then enoughL nuclei are formed to make unnecessary a later «x process ». Consideration of the energy spectrum suggests that most of the low-energy cosmic radiation may be due to shock acceleration, and much of the high-energy part due to pulsar acceleration.