http://arxiv.org/abs/1910.07528
For the first time, we characterize the rigidity regimes of the diffusion coefficient $\kappa$ for arbitrary rigidities and guide fields, which we derive as a function of physical and numerical parameters. We show that at turbulence levels above 5\% of the total magnetic field, the approximation of an energy dependence $\kappa\propto E^{1/3}$ as predicted for a Kolmogorov spectrum within Quasi-Linear Theory does not hold. Consequently, a proper description of cosmic-ray propagation can only be achieved by using a turbulence-level dependent diffusion coefficient and can contribute to solving the Galactic cosmic-ray gradient problem.
P. Reichherzer, J. Tjus, E. Zweibel, et. al.
Fri, 18 Oct 19
41/77
Comments: 18 pages, 6 figures