Tuesday, November 20, 2012

1211.4356 (Dominik R. G. Schleicher et al.)

Magnetic fields during high redshift structure formation    [PDF]

Dominik R. G. Schleicher, Muhammad Latif, Jennifer Schober, Wolfram Schmidt, Stefano Bovino, Christoph Federrath, Jens Niemeyer, Robi Banerjee, Ralf S. Klessen
We explore the amplification of magnetic fields in the high-redshift Universe. For this purpose, we perform high-resolution cosmological simulations following the formation of primordial halos with \sim10^7 M_solar, revealing the presence of turbulent structures and complex morphologies at resolutions of at least 32 cells per Jeans length. Employing a turbulence subgrid-scale model, we quantify the amount of unresolved turbulence and show that the resulting turbulent viscosity has a significant impact on the gas morphology, suppressing the formation of low-mass clumps. We further demonstrate that such turbulence implies the efficient amplification of magnetic fields via the small-scale dynamo. We discuss the properties of the dynamo in the kinematic and non-linear regime, and explore the resulting magnetic field amplification during primordial star formation. We show that field strengths of \sim10^{-5} G can be expected at number densities of \sim5 cm^{-3}.
View original: http://arxiv.org/abs/1211.4356

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