Non-linear momentum diffusion of heliospheric cosmic rays |
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Authors: | A Shalchi |
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Institution: | Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany |
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Abstract: | Besides parallel and perpendicular spatial diffusion, momentum diffusion can be seen as the third important process of cosmic ray transport. In this paper, the recently derived weakly non-linear theory is applied for a simple quasi-magnetostatic composite model to determine the momentum diffusion coefficient. It is demonstrated that non-linear effects are essential and cannot be neglected. Therefore, the weakly non-linear transport theory has to be preferred over the traditional quasi-linear approach. Within this improved theory, we find for the rigidity dependence of the momentum diffusion coefficient A ~ R 1.4 for relativistic and A ~ R 0.4 for non-relativistic cosmic rays. |
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Keywords: | diffusion turbulence cosmic rays |
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