Astrophysics and Space Science

, Volume 68, Issue 1, pp 27–48 | Cite as

A diffusion model for cosmic ray propagation in the Galaxy

  • Jon M. Wallace
Article

Abstract

A diffusion model for the propagation of relativistic nuclear cosmic rays in the Galaxy is developed. The model has two nonstandard features: The escape of cosmic-ray particles from the Galaxy is simulated by a term in the diffusion equations, rather than the imposition of boundary conditions on the diffusion solution at the surface of the confinement region. And an age-dependent, locally-averaged effective gas distribution is employed in the diffusion equations. The model simulates free-particle outflow at the Galactic boundary. The model is fit to chemical composition data in the 0.3–5 GeV per nucleon range. It is then consistent with the large-scale Galactic γ-ray data, radio halo data, energy constraints on the assumed supernova sources, and, when extended to very high energies, cosmic-ray anisotrophy data. From the fit we conclude that the cosmic rays are confined in a large flattened or quasis-pherical halo with a scale height in the range 3–6 kpc and an average Galactic escape time of ∼108 yr.

Keywords

Diffusion Model Diffusion Equation Scale Height Diffusion Solution Energy Constraint 

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References

  1. Buffington, A., Orth, C. D. and Mast, T. S.: 1978,Phys. Rev. Lett. 41, 594.Google Scholar
  2. Bulanov, S. V., Syrovatskii, E. I. and Dogiel, V. A.: 1976,Astrophys. Space Sci. 44, 255.Google Scholar
  3. Burbidge, G.: 1969,Comm. Astrophys. Space Phys. 1, 25.Google Scholar
  4. CERN-Pisa-Rome-Stony Brook Collaboration: 1976,Phys. Lett. 63B, 460.Google Scholar
  5. Colgate, S. A. and White, R. H.: 1966,Astrophys. J. 143, 626.Google Scholar
  6. Dickinson, G. J. and Osborne, J. L.: 1974,J. Phys. A 7, 728.Google Scholar
  7. Dodds, D., Strong, A. W. and Wolfendale, A. W.: 1975,Monthly Notices Roy. Astron. Soc. 171. 569.Google Scholar
  8. Ekers, R. D.: 1975, in G. Setti (ed.),Structure and Evolution of Galaxies, p. 217, Reidel, Dordrecht.Google Scholar
  9. Fermilab Single Arm Spectrometer Group: 1975,Phys. Rev. Lett. 35, 1195.Google Scholar
  10. Fichtel, C. E., Hartman, R. C., Kniffen, D. A., Thompson, D. J., Bignami, G. F., Ögelman, H., Ozel, M. E. and Tumer, T.: 1975,Astrophys. J. 198, 163.Google Scholar
  11. Garcia-Muñoz, M., Mason, G. M. and Simpson, J. A.: 1975a,Astrophys. J. 201, L141.Google Scholar
  12. Garcia-Muñoz, M., Mason, G. M. and Simpson, J. A.: 1975b,Astrophys. J. 201, L145.Google Scholar
  13. Ginzburg, V. L. and Ptuskin, V. S.: 1976,Rev. Mod. Phys. 48, 161.Google Scholar
  14. Ginzburg, V. L. and Syrovatskii, S. I.: 1964,The Origin of Cosmic Rays, Pergamon, London and New York.Google Scholar
  15. Ginzburg, V. L. and Syrovatskii, S. I.: 1971,12th Intern. Conf. on Cosmic Rays, Hobart, Invited and Reported Papers, p. 53.Google Scholar
  16. Gold, T.: 1969,Nature 221, 25.Google Scholar
  17. Hagan, F. A., Fisher, A. J. and Ormes, J. F.: 1977,Astrophys. J. 212, 262.Google Scholar
  18. Hillas, A. M. and Ouldridge, M.: 1975,Nature 253, 609.Google Scholar
  19. Jokipii, J. R.: 1976,Astrophys. J. 208, 900.Google Scholar
  20. Kodaira, K.: 1974,Publ. Astron. Soc. Japan. 26, 255.Google Scholar
  21. Le Guet, F. and Stanton, M.: 1974,Astron. Astrophys. 35, 165.Google Scholar
  22. Lingenfelter, R. E.: 1973,Astrophys. Space Sci. 24, 83.Google Scholar
  23. Meneguzzi, M., Audouze, J. and Reeves, H.: 1971,Astron. Astrophys. 15, 337.Google Scholar
  24. Pacheco de Freitas, J. A.: 1971,Astron. Astrophys. 13, 58.Google Scholar
  25. Preszler, A. M., Kish, J. C., Lezniak, J. A., Simpson, G., and Webber, W. R.: 1975,14th Intern. Conf. on Cosmic Rays, Munich, Conference Papers12, 4096.Google Scholar
  26. Ptuskin, V. S.: 1972,Kosmich. Issled. 10, 351.Google Scholar
  27. Ptuskin, V. S.: 1974,Astrophys. Space Sci. 28, 17.Google Scholar
  28. Ramaty, R. and Lingenfelter, R. E.: 1971,Isotopic Composition of the Primary Cosmic Radiation, p. 203, Danish Space Research Institute.Google Scholar
  29. Ramaty, R., Reames, D. V. and Lingenfelter, R. E.: 1970,Phys. Rev. Lett. 24, 913.Google Scholar
  30. Renberg, P. U.: 1972,Nucl. Phys. A183, 81.Google Scholar
  31. Scott, J. S.: 1975,Nature 258, 58.Google Scholar
  32. Shapiro, M. M. and Silberberg, R.: 1970,Ann. Rev. Nucl. Sci. 20, 323.Google Scholar
  33. Shklovski, I. S.: 1968,Supernovae, Interscience, New York.Google Scholar
  34. Silberberg, R. and Tsao, C. H.: 1973,Astrophys. J. Suppl. 25, 315.Google Scholar
  35. Stecker, F. W.: 1975,Phys. Rev. Lett. 35, 188.Google Scholar
  36. Stecker, F. W.: 1977,Astrophys. J. 212, 60.Google Scholar
  37. Stecker, F. W. and Jones, F. C.: 1977,Astrophys. J. 217, 843.Google Scholar
  38. Stecker, F. W., Solomon, P. M., Scoville, N. Z. and Ryter, C. E.: 1975,Astrophys. J. 201, 90.Google Scholar
  39. van der Kruit, P. C. and Allen, R. J.: 1976,Ann. Rev. Astron. Astrophys. 14, 417.Google Scholar
  40. Webber, W. R., Lezniak, J. A., Kish, J. and Damle, S. V. 1973,Astrophys. Space Sci. 24, 17.Google Scholar
  41. Webster, A.: 1975,Monthly Notices Roy. Astron. Soc. 171 243.Google Scholar
  42. Wentzel, D. G.: 1969,Astrophys. J. 156, 303.Google Scholar
  43. Wilson, J. R.: 1974,Phys. Rev. Lett. 32, 849.Google Scholar

Copyright information

© D. Reidel Publishing Co 1980

Authors and Affiliations

  • Jon M. Wallace
    • 1
  1. 1.Los Alamos Scientific LaboratoryLos AlamosU.S.A.

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