Propagation studies related to the origin of cosmic rays

Propagation of cosmic rays is studied in an investigation of the origin of cosmic rays. An accurate method is presented to correct for spallation effects on the cosmic-ray nuclei during their transport from the sources subsequent to their acceleration. The composition of cosmic rays at the source is discussed with emphasis on its implications on their origin, and the effects of stochastic acceleration in the interstellar medium on the relative spectra of primaries and secondaries are examined to show that the observation of decreasing relative abundance of secondaries with increasing energy rules out such phenomena for galactic cosmic rays. Contributions to the spectra from a discrete set of sources at various distances from the solar system on the galactic plane are considered, and it is shown that unless there are at least 30,000 sources of actively accelerating cosmic rays in the Galaxy, the spectrum of electrons would have a premature cutoff at high energies.