Non-diffusive transport in plasma turbulence: a fractional diffusion approach
Abstract
Numerical evidence of non-diffusive transport in three-dimensional, resistive pressure-gradient-driven plasma turbulence is presented. It is shown that the probability density function (pdf) of test particles' radial displacements is strongly non-Gaussian and exhibits algebraic decaying tails. To model these results we propose a macroscopic transport model for the pdf based on the use of fractional derivatives in space and time, that incorporate in a unified way space-time non-locality (non-Fickian transport), non-Gaussianity, and non-diffusive scaling. The fractional diffusion model reproduces the shape, and space-time scaling of the non-Gaussian pdf of turbulent transport calculations. The model also reproduces the observed super-diffusive scaling.
Cite
@article{arxiv.physics/0403039,
title = {Non-diffusive transport in plasma turbulence: a fractional diffusion approach},
author = {D. del-Castillo-Negrete and B. A. Carreras and V. E. Lynch},
journal= {arXiv preprint arXiv:physics/0403039},
year = {2009}
}