Astron. Astrophys. 326, 793-800 (1997)

Simulations of cosmic ray cross field diffusion
in highly perturbed magnetic fields

G. Michaek ¹ and M. Ostrowski <sup>1, 2

1</sup> Obserwatorium Astronomiczne, Uniwersytet Jagielloski, ul.Orla 171, Pl-30-244 Kraków, Poland
² Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany

Received 10 January 1997 / Accepted 20 May 1997

Abstract

The process of particle cross-field diffusion in high amplitude Alfvénic turbulence is considered using the method of the Monte Carlo particle simulations. We derive the cross-field diffusion coefficient and the parallel diffusion coefficient in the presence of different 1-D, 2-D and 3-D turbulent wave field models and discuss the , and variations with the wave amplitude. is compared also to the respective derived values of the magnetic field diffusion coefficient. We note substantial differences in the cross-field diffusion efficiency at the same perturbation amplitude, depending on the detailed form of the turbulent field considered. Vanishing of at 1-D and 2-D turbulent fields is confirmed. For some types of the turbulent magnetic field an initial regime of sub-diffusive transport appears in the simulations. The derived values of are weakly dependent on the wave form and scale as the inverse of the squared perturbation amplitude up to our highest non-linear amplitudes.

Key words: cosmic rays MHD-turbulence acceleration of particles diffusion

Send offprint requests to: G. Michalek (michalek@oa.uj.edu.pl)

Contents

• 1. Introduction
• 2. Description of simulations
  • A. Linearly polarized plane waves
  • B. Wave packets
  • Testing the simulation scheme
  • Magnetic field line diffusion coefficient
• 3. Results and discussion
• 4. Final remarks
• Acknowledgements
• Appendix A: summary of notation
• References

© European Southern Observatory (ESO) 1997

Online publication: November 3, 1997
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