EVIDENCE FOR THE NONLINEAR TRANSPORT OF GALACTIC COSMIC RAYS

摘要

The measured decrease of the abundance ratio of secondary to primary Galactic cosmic-ray nuclei is explained by the increase of the cosmic-ray parallel mean free path with magnetic rigidity λ_(‖) ∝ R~(0.6) that results from the weakly nonlinear transport theory of cosmic rays in the turbulent Galactic magnetic fields. Because the ratio of fluctuating to ordered magnetic fields in the Galaxy q_L = (δB/B_0)~2 is large, this nonlinear transport theory has to be favored over the traditional quasi-linear theory that requires very small values q_L < < 1. Our explanation provides an alternative to Galactic transport theories of cosmic rays with significant distributed stochastic acceleration.