Clustering of passive impurities in magnetohydrodynamic turbulence

Abstract

The transport of heavy, neutral, or charged pointlike particles by three-dimensional incompressible, resistive magnetohydrodynamic turbulence is investigated by means of high-resolution numerical simulations. The spatial distribution of such impurities is observed to display strong deviations from homogeneity, both at dissipative and inertial range scales. Neutral particles tend to cluster in the vicinity of coherent vortex sheets due to their viscous drag with the flow, leading to the simultaneous presence of very concentrated and almost empty regions. The signature of clustering is different for charged particles because they are influenced both by the drag and the Lorentz forces. The regions of spatial inhomogeneities change due to attractive and repulsive vortex sheets. While small charges increase clustering, larger charges have a reverse effect. © 2009 American Institute of Physics.