Studies of the particle diffusion coefficient in the fluctuating magnetic field by the direct-interaction approximation
Abstract
The particle diffusion in a stochastic magnetic field is investigated by using the functional integral method. With the ensemble average of a functional representation to a kinetic equation over the fluctuating magnetic field and the random variables modeling the Coulomb collisions, a closed set of equations for an ensemble-averaged distribution function and a response function to an infinitesimal external perturbation is derived within the framework of the direct-interaction (DIA). By using the Markovian approximation to the equation for the response function, the cross-field diffusion coefficients are found to be obtained from nonlinear ordinary differential equations. Explicitly calculated diffusion coefficients for various parameters are also shown in the shearless and sheared configurations.
- Publication:
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Journal of Plasma Physics
- Pub Date:
- August 2005
- DOI:
- Bibcode:
- 2005JPlPh..71..449T