Anomalous diffusion, clustering, and pinch of impurities in plasma edge turbulence
Abstract
The turbulent transport of impurity particles in plasma edge turbulence is investigated. The impurities are modeled as a passive fluid advected by the electric and polarization drifts, while the ambient plasma turbulence is modeled using the two-dimensional Hasegawa--Wakatani paradigm for resistive drift-wave turbulence. The features of the turbulent transport of impurities are investigated by numerical simulations using a novel code that applies semi-Lagrangian pseudospectral schemes. The diffusive character of the turbulent transport of ideal impurities is demonstrated by relative-diffusion analysis of the evolution of impurity puffs. Additional effects appear for inertial impurities as a consequence of compressibility. First, the density of inertial impurities is found to correlate with the vorticity of the electric drift velocity, that is, impurities cluster in vortices of a precise orientation determined by the charge of the impurity particles. Second, a radial pinch scaling linearly with the mass--charge ratio of the impurities is discovered. Theoretical explanation for these observations is obtained by analysis of the model equations.
Keywords
Cite
@article{arxiv.physics/0501039,
title = {Anomalous diffusion, clustering, and pinch of impurities in plasma edge turbulence},
author = {M. Priego and O. E. Garcia and V. Naulin and J. Juul Rasmussen},
journal= {arXiv preprint arXiv:physics/0501039},
year = {2009}
}
Comments
This article has been submitted to Physics of Plasmas. After it is published, it will be found at http://pop.aip.org/pop/