Tsallis statistics as a tool for studying interstellar turbulence

Abstract

We used magnetohydrodynamic (MHD) simulations of interstellar turbulence to study the probability distribution functions (PDFs) of increments of density, velocity, and magnetic field. We found that the PDFs are well described by a Tsallis distribution, following the same general trends found in solar wind and electron MHD studies. We found that the PDFs of density are very different in subsonic and supersonic turbulence. In order to extend this work to ISM observations, we studied maps of column density obtained from three-dimensional MHD simulations. From the column density maps, we found the parameters that fit to Tsallis distributions and demonstrated that these parameters vary with the sonic and Alfvén Mach numbers of turbulence. This opens avenues for using Tsallis distributions to study the dynamical and perhaps magnetic states of interstellar gas. © 2010. The American Astronomical Society. All rights reserved.