TURBULENT AMPLIFICATION AND STRUCTURE OF THE INTRACLUSTER MAGNETIC FIELD
抄録
<jats:title>ABSTRACT</jats:title> <jats:p>We compare DNS calculations of homogeneous isotropic turbulence with the statistical properties of intracluster turbulence from the Matryoshka Run and find remarkable similarities between their inertial ranges. This allowed us to use the time-dependent statistical properties of intracluster turbulence to evaluate dynamo action in the intracluster medium, based on earlier results from a numerically resolved nonlinear magneto-hydrodynamic turbulent dynamo. We argue that this approach is necessary (a) to properly normalize dynamo action to the available intracluster turbulent energy and (b) to overcome the limitations of low Re affecting current numerical models of the intracluster medium. We find that while the properties of intracluster magnetic field are largely insensitive to the value and origin of the seed field, the resulting values for the Alfvén speed and the outer scale of the magnetic field are consistent with current observational estimates, basically confirming the idea that the magnetic field in today’s galaxy clusters is a record of its past turbulent activity.</jats:p>
収録刊行物
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- The Astrophysical Journal
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The Astrophysical Journal 817 (2), 127-, 2016-01-27
American Astronomical Society