PLASMA TRANSPORT IN THE INTERPLANETARY SPACE - PERCOLATION AND ANOMALOUS DIFFUSION OF MAGNETIC-FIELD LINES

The magnetic fluctuations due to, e.g., magnetohydrodynamic turbulence cause a magnetic-field line random walk that influences many cosmic p lasma phenomena. The results of a three-dimensional numerical simulati on of a turbulent magnetic field in plane geometry are presented here. Magnetic percolation, Levy flights, and non-Gaussian random walk of t he magnetic-field lines are found for moderate perturbation levels. In such a case plasma transport can be anomalous, i.e., either superdiff usive or subdiffusive. Increasing the perturbation level a Gaussian di ffusion regime is attained. The implications on the structure of the e lectron foreshock and of planetary magnetopauses are discussed.