Statistical Properties of Magnetic Fields in Simulated Galaxy Clusters

Hilary Egan, University of Colorado

The intracluster medium is a magnetized fluid with very large mean free paths. Although this validates a fluid approach at large scales, at scales below the resolution of typical simulations, magnetic field-driven instabilities can grow. These instabilities could propagate to larger scales, having strong effects on the viscosity, conductivity and turbulence in the ICM. One way to circumvent this resolution-driven problem is to create sub-grid models of the instabilities using high-resolution simulations of small volumes; however, the plasma properties of the high-resolution simulation must be broadly applicable in order for the sub-grid models to be appropriate. Here I present an analysis of plasma properties across 10 clusters with a variety of sizes and dynamical states simulated at high resolution using ideal MHD Enzo. Using multiple metrics including coherence length, Debeye length, and anisotropy parameter, we find that each measure shows strong similarity across clusters. By showing that these properties are homogeneous across clusters, we find that sub-grid models are both needed and scientifically justifiable.

Abstract Author(s): Hilary Egan, Brian O'Shea, Eric Hallman, Jack Burns