Abstract
Particle fluxes and pitch angle distributions of relativistic solar protons at Earth's orbit have been determined by Monte Carlo calculations. The analysis covers two hours after the release of the particles from the Sun and total of 8 × 106 particle trajectories were simulated. The pitch angle scattering was assumed to be isotropic and the scattering mean free path was varied from 0.1 to 4 AU.
The intensity-time profiles after a delta-like injection from the Sun show that the interplanetary propagation is clearly non-diffusive at scattering mean-free paths above 0.5 AU. All pitch angle distributions have a steady minimum at 90 °, and they become similar about 20 min after the arrival of first particles.
As an application, the solar injection profile and the interplanetary scattering mean-free path of particles that gave rise to the GLE on 7 May, 1978 were determined. In contrast to the values of 3–5 AU published by other authors, the average scattering mean-free path was found to be about 1 AU.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Debrunner, H. and Lockwood, J. A.: 1980, J. Geophys. Res. 85, 6853.
Debrunner, H., Flückiger, E., Neuenschwander, H., Schubnell, M., and Lockwood, J. A.: 1983, Proc. 18th Int. Cosmic Ray Conf. 4, 144.
Duggal, S. P.: 1979, Rev. Geophys. Space Phys. 17, 1021.
Lockwood, J. A., Debrunner, H., Flückiger, E., Neuenschwander, H., and Schubnell, M.: 1982, J. Geophys. Res. 87, 4338.
Olson, W. P. and Pfitzer, K. A.: 1974, J. Geophys. Res. 79, 3739.
Peddie, N. W. and Fabiano, E. B.: 1976, J. Geophys. Res. 81, 2539.
Shea, M. A., Smart, D. F., Arens, M., Bercovitch, M., Chiba, T., Debrunner, H., Dorman, L. I., Duggal, S. P., Fenton, A. G., Flückiger, E., Galli, M. Hatton, C. J., Humble, J. E., Jodogne, J. C., König, P. J., Lazutin, L. L., Lockwood, J. A., Pomerantz, M. A., Röhrs, K., Shafer, Yu. G., Stoker, P. H., Storini, M., Takahashi, H., Tanskanen, P. J., Venkatesan, D., Wada, M., and Wibberenz, G.: 1979, Proc. 18th Int. Cosmic Ray Conf. 5, 226.
Smart, D. F., Shea, M. A., and Tanskanen, P. J.: 1971, Proc. 12th Int. Cosmic Ray Conf. 2, 483. Solar-Geophysical Data, 1978, No. 411.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lumme, M., Nieminen, M., Torsti, J.J. et al. Interplanetary propagation of relativistic solar protons. Sol Phys 107, 183–194 (1986). https://doi.org/10.1007/BF00155352
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00155352