Cosmic magnetism from a computational perspective
I will present a recent numerical study on the generation and the amplification of magnetic fields in the Universe. Through cosmological simulations of galaxy formation, we have studied the Biermann battery process that drives microscopic current and creates weak fields both in the linear and in the non-linear regime of structure formation. The next step in this Cosmic Dynamo is a fast amplification of the field through a turbulent dynamo driven by strong galactic winds at high redshift. After quickly reviewing the basic processes governing the turbulent dynamo, I will present a numerical experiment of a fast turbulent dynamo in a dwarf galaxy, highlighting the need for high spatial resolution. Finally, I will present recent results on the cosmic history of the magnetic field in a Milky-Way-like galaxy, using for the small scale turbulent dynamo a subgrid model that can overcome these difficult resolution requirements.