Astrophysics and Space Science

, Volume 86, Issue 1, pp 185–195 | Cite as

Study of parallel diffusion of energetic particles in the interplanetary medium using spacecraft data at 1 and 5 AU

  • X. Moussas
  • J. J. Quenby
  • J. F. Valdes Galicia
Article

Abstract

Energetic particle (1–100 MeV) pitch angle scattering in the Interplanetary Magnetic Field (IMF) is studied using spacecraft magnetometer data at 1 AU (IMP 7 and HEOS 2) and at 5 AU (Pioneer 10). Particle trajectories are followed by a computer simulation of their movement in a realistic model of the IMF. Determination of the pitch angle diffusion coefficient at 1 AU (Dμμ) leads to a parallel mean free path which is roughly independent of particle energy, λ≃0.03 AU. At the lowest energy our result is at least a factor of 3 larger than the predictions of quasi linear theory. Results at 5 AU lead to a radial mean free path which is between 2 to 6 times smaller than at 1 AU, probably indicating a greater importance for perpendicular diffusion at large heliodistances. In fact a roughly constant radial mean free path (λ r ≃0.01 AU) is obtained when the contribution of perpendicular diffusion at 5 AU is taken into account (Moussaset al., 1981).

Keywords

Diffusion Coefficient Free Path Linear Theory Realistic Model Pitch Angle 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Cecchini, S., Moussas, X., and Quenby, J. J.: 1980,Astrophys. Space Sci. 69, 425.Google Scholar
  2. Earl, J.: 1976,Astrophys. J. 205, 900.Google Scholar
  3. Earl, J.: 1981,Proc. 17th Int. C.R. Conf. 3, 385.Google Scholar
  4. Erdös, G. and Richardson, I.: 1981 (private communication).Google Scholar
  5. Fisk, L. A.: 1976,J. Geophys. Res. 81, 4641.Google Scholar
  6. Fisk, L. and Axford, I.: 1969,J. Geophys. Res. 74, 1973.Google Scholar
  7. Gleeson, L. and Axford, I.: 1968,Astrophys. J. 154, 1011.Google Scholar
  8. Goldstein, M. L.: 1976,Astrophys. J. 204, 900.Google Scholar
  9. Goldstein, M. L.: 1977,J. Geophys. Res. 82, 1071.Google Scholar
  10. Gombosi, T. I. and Owens, A. J.: 1979,Proc. 16th Int. C.R. Conf., Kyoto 3, 25.Google Scholar
  11. Hasselman, K. and Wibberenz, G.: 1970,Astrophys. J. 162, 1049.Google Scholar
  12. Hasselman, K. and Wibberenz, G.: 1968,Z. Geophys. 34, 553.Google Scholar
  13. Hamilton, D. C.: 1977,J. Geophys. Res. 82, 2157.Google Scholar
  14. Hedgecock, P.: 1975,Solar Phys. 42, 497.Google Scholar
  15. Jokipii, J. R.: 1966,Astrophys. J. 146, 480.Google Scholar
  16. Jokipii, J. R.: 1971,Rev. Geophys. Space Phys. 9, 27.Google Scholar
  17. Jones, F. C., Kaiser, T. B., and Birmingham, T. J.: 1973,Proc. 13th Int. C.R. Conf., Denver 2, 669.Google Scholar
  18. Jones, F. C., Kaiser, T. B., and Birmingham, T. J.: 1978,Phys. Fluids 21, 361.Google Scholar
  19. Jones, F. C., Kaiser, T. B., and Birmingham, T. J.: 1978b,Phys. Fluids 21, 370.Google Scholar
  20. Kolomeets, G. V., Sevastionaou, U. N., and Stekolnikov, N. V.: 1981,Proc. 17th Int. C.R. Conf., Paris 3, 322.Google Scholar
  21. Kato, M., Sakai, T., and Tamai, E.: 1981,Proc. 17th Int. C.R. Conf., Paris 3, 314.Google Scholar
  22. Kunow, H., Wibberenz, G., Green, R., Muller-Mellin, R., Witte, M., Hempe, H., Mewladt, R. A., Stone, E. C., and Vogt, R. E.: 1977,Proc. 15th Int. C.R. Conf., Plovdiv 3, 227.Google Scholar
  23. Lupton, J. E. and Stone, E. C.: 1973,J. Geophys. Res. 78, 1007.Google Scholar
  24. Ma Sung, L.: 1977, PhD Thesis, (U. of Maryland).Google Scholar
  25. McKibben, R. B., Pyle, K. B., Simpson, J. A., Tozzolino, A. J., and O'Gallagher, J. J.: 1975,Proc. 14th Int. C.R. Conf., Munich 4, 1412.Google Scholar
  26. Meyer, P., Parker, G. N., and Simpson, J. A.: 1956,Phys. Rev. 104, 768.Google Scholar
  27. Morfill, G. E., Völk, J. J., and Lee, M. A.: 1976,J. Geophys. Res. 81, 5841.Google Scholar
  28. Morfill, G., Richter, A. K., and Scholer, M.: 1979,J. Geophys. Res. 84, 1505.Google Scholar
  29. Moussas, X., Quenby, J. J., and Webb, S.: 1975,Proc. 14th Int. C.R. Conf., Munich 3, 866.Google Scholar
  30. Moussas, X. and Quenby, J. J.: 1978,Astrophys. Space Sci. 56, 483.Google Scholar
  31. Moussas, X., Quenby, J. J., and Valdes Galicia, J. F.: 1981,17th Int. C.R. Conf. Paris 10, 101.Google Scholar
  32. Moussas, X., Quenby, J. J., and Valdes Galicia, J. F.: 1982,Astrophys. Space Sci. 86, 197 (this issue).Google Scholar
  33. Ng, C. K. and Gleeson, L. J.: 1971,Proc. 12th Int. C.R. Conf., Hobart 2, 498.Google Scholar
  34. Palmer, I. D., Zwickl, R. D., Webber, W. R., and McDonald, E. B.: 1977, referred in Zwickl and Webber.Google Scholar
  35. Parker, E.N.: 1965,Planet. Space Sci. 13, 9.Google Scholar
  36. Roelof, E. C. and Krimigis, S. M.: 1973,J. Geophys. Res. 78, 5375.Google Scholar
  37. Thomas, B. and Smith, E. J.: 1980,J. Geophys. Res. 85, 6861.Google Scholar
  38. Völk, H. J.: 1975,Rev. Geophys. Space Phys. 13, 547.Google Scholar
  39. Webb, S. and Quenby, J.J.: 1973,Planet. Space Sci. 21, 23.Google Scholar
  40. Webb, S., Balogh, A., Quenby, J. J., and Sear, J. F.: 1973,Solar Phys. 29, 477.Google Scholar
  41. Wibberenz, G.: 1979,Proc. 16th Int. C.R. Conf., Kyoto (Rapporteur),14, 234.Google Scholar
  42. Zwickl, R. D. and Webber, W. R.: 1977,Solar Phys. 54, 457.Google Scholar
  43. Zwickl, R. D. and Webber, W. R.: 1978,J. Geophys. Res. 83, 1157.Google Scholar

Copyright information

© D. Reidel Publishing Co 1982

Authors and Affiliations

  • X. Moussas
    • 1
  • J. J. Quenby
    • 2
  • J. F. Valdes Galicia
    • 2
  1. 1.National University of AthensGreece
  2. 2.The Blackett LaboratoryImperial CollegeLondonEngland

Personalised recommendations