Abstract
It is shown that the velocity term, occurring in the expression for the rate of energy gain by the Fermi mechanism of acceleration, is to be taken into account in case of acceleration of non-relativistic particles. A spectral form of accelerated particles is derived on this basis and is called the ‘Fermi Spectrum’. At non-relativistic energies this spectral form is significantly different from the currently used forms of power law in total energy per nucleon and in rigidity, and lies about midway between them. It is shown that using this form of source spectrum of cosmic ray nuclei, satisfactory agreement can be obtained between the calculated values and the observed ones of the ratios of H2/He4 and He3/He4, and the energy spectra of protons and helium nuclei near the Earth.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Comstock, G. M., Hsieh, K. C., and Simpson, J. A.: 1971,Astrophys. J., to be published.
Fermi, E.: 1949,Phys. Rev. 75, 1169.
Meyer, J. P.: 1971,Proc. 12th International Conference on Cosmic Rays Hobart, to be published.
Parker, E. N.: 1969,Proc. of the Colloquium on Cosmic Ray Studies in Relation to Recent Advances in Astronomy and Astrophysics (ed. by R. R. Daniel, P. J. Lavakare and S. Ramadurai), Tata Institute of Fundamental Research, Bombay, p. 301.
Ramadurai, S. and Biswas, S.: 1971,Proc. 12th International Conference on Cosmic Rays, Hobart, vol.2, p. 793.
Simpson, J. A.: 1971,Proc. 12th International Conference on Cosmic Rays, Hobart, rapporteur paper, to be published.
Urch, I. H. and Gleeson, L. J.: 1972,Astrophys. Space Sci. 16, 55.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ramadurai, S., Biswas, S. The fermi mechanism and the source spectrum of cosmic ray nuclei. Astrophys Space Sci 17, 467–471 (1972). https://doi.org/10.1007/BF00642916
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00642916