Diffusive propagation of cosmic rays from supernova remnants in the Galaxy. I: spectrum and chemical composition
In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for different choices of the diffusion coefficient D(E) experienced by c...
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Published in | Journal of cosmology and astroparticle physics Vol. 2012; no. 1; pp. 010 - 28 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
IOP Publishing
01.01.2012
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Subjects | |
Online Access | Get full text |
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Summary: | In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for different choices of the diffusion coefficient D(E) experienced by cosmic rays during propagation in the Galaxy. We find that the stochastic fluctuations induced by the spatial and temporal distribution of supernovae, together with the effect of spallation of nuclei, lead to mild but sensible violations of the simple, leaky-box-inspired rule that the spectrum observed at Earth is N(E) proportional to E super(- alpha ) with alpha = gamma + delta , where gamma is the slope of the cosmic ray injection spectrum at the sources. We also comment on the effect of time dependence of the escape of cosmic rays from supernova remnants, and of a possible clustering of the sources in superbubbles. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1475-7516 1475-7516 |
DOI: | 10.1088/1475-7516/2012/01/010 |