The Magnetothermal Instability and its Applications to Clusters of Galaxies

Ian Parrish, Princeton University

The Magnetothermal Instability (MTI) is a plasma instability that occurs in dilute, magnetized astrophysical plasmas. The driving force is anisotropic thermal transport that occurs along magnetic field lines. In this regime, the criterion for convective stability is significantly modified. We use the magnetohydrodynamics (MHD) code Athena with an anisotropic conduction module to simulate this instability. In 2D we show excellent agreement between measured growth rates and linear theory. We follow the instability into the nonlinear regime to show that it can completely rearrange an atmosphere to a fully isothermal state. In 3D we show that the MTI drives a magnetic dynamo and efficiently transports heat. Finally, we demonstrate the application of this instability to the intracluster medium of clusters of galaxies and compare to X-ray observations.

Abstract Author(s): Ian J. Parrish and James M. Stone