Parallel and Perpendicular Diffusion of Cosmic Rays in Turbulent Plasmas: Analytical Theory and Simulation

Abstract:

A fundamental problem in Space Science and Astrophysics is the interaction
between energetic particles and a turbulent plasma. We have developed a
test-particle code to simulate the interaction of charged particles with
turbulent magnetic fields. Diffusion coefficients along and across the
mean magnetic field are calculated and compared to different analytical
theories. Different turbulence models where considered such as models
with reduced dimensionality and full three-dimensional models. We have
also included wave propagation effects. We explored the transport regimes
in which the Bohm limit and the quasilinear limit are valid. We have also shown
that for perpendiculear diffusion the so-called unified nonlinear transport
theory agrees very well with the numerical simulations.