Cosmic-Ray Propagation in Inhomogeneous Largescale Magnetic Fields - a Pitch-Angle Diffusion and Convection
A drift kinetic theory of cosmic-ray (CR) propagation in inhomogeneous random large-scale magnetic fields (MF) is considered. An averaging of the drift kinetic equation for CR particles distribution was performed in the statistical ensemble of MF realization, whereby the curvature radius of randomly wandering MF is much larger than gyro-radiusR H of CR particles. Collisions of CR particles on the small-scale MF inhomogeneities with the characteristics scalel O ≪R H is not taken into account. It is proved that this random MF raises non-zero pitch-angle diffusion of the CR particles, which is very strong for particles with zero pitch angle. The transport equation is derived for a case of weak inhomogeneity of the random MF in the direction of MF mean value. In this case additional convection of particles in the direction of energy density gradient of random MF variables.