Dynamo in the Intra-Cluster Medium: Simulation of CGL-MHD Turbulent Dynamo

Type Conference Paper
Names R. Santos-Lima, E. M. de Gouveia Dal Pino, A. Lazarian, G. Kowal, D. Falceta-Gonçalves
Conference Name IAU Symposium
Volume 274
Pages 482-484
Date June 1, 2011
Short Title Dynamo in the Intra-Cluster Medium
URL http://adsabs.harvard.edu/abs/2011IAUS..274..482S
Library Catalog NASA ADS
Abstract The standard magnetohydrodynamic (MHD) description of the plasma in the hot, magnetized gas of the intra-cluster (ICM) medium is not adequate because it is weakly collisional. In such collisionless magnetized gas, the microscopic velocity distribution of the particles is not isotropic, giving rise to kinetic effects on the dynamical scales. These kinetic effects could be important in understanding the turbulence as well as the amplification and maintenance of the magnetic fields in the ICM. It is possible to formulate fluid models for collisonless or weakly collisional gas by introducing modifications in the MHD equations. These models are often referred as kinetic MHD (KMHD). Using a KMHD model based on the CGL-closure, which allows the adiabatic evolution of the two components of the pressure tensor (the parallel and perpendicular components with respect to the local magnetic field), we performed 3D numerical simulations of forced turbulence in order to study the amplification of an initially weak seed magnetic field. We found that the growth rate of the magnetic energy is comparable to that of the ordinary MHD turbulent dynamo, but the magnetic energy saturates in a level smaller than that of the MHD case. We also found that a necessary condition for the dynamo to operate is to impose constraints on the anisotropy of the pressure.
Tags MHD, Magnetic Fields, Plasmas, intergalactic medium
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