Diffusion of stochastic magnetic field lines with average poloidal magnetic component

Abstract

We study the diffusion of stochastic isotropic and anisotropic magnetic field lines in turbulence with average poloidal magnetic field component. In the current work we employ the so-called DeCorrelation Trajectory method in order to compute the running and asymptotic diffusion coefficients of stochastic magnetic field lines with average poloidal magnetic field component. A modification of the diffusion coefficients is caused by the average magnetic field component parameter in the presence of trajectory trapping. We calculate the field line diffusion coefficients Dxx and Dyy for different values of the magnetic Kubo number K, the average magnetic field component parameter Kav and the anisotropy parameter Λ. Furthermore we compare our new findings with those already obtained in papers dealing with the calculus of the diffusion coefficients for a stochastic sheared magnetic field.