Turbulent Magnetogenesis in a Collisionless Plasma

We demonstrate an efficient mechanism for generating magnetic fields in turbulent, collisionless plasmas. By using fully kinetic, particle-in-cell simulations of an initially nonmagnetized plasma, we inspect the genesis of magnetization, in a nonlinear regime. The complex motion is initiated via a Taylor-Green vortex, and the plasma locally develops strong electron temperature anisotropy, due to the strain tensor of the turbulent flow. Subsequently, in a domino effect, the anisotropy triggers a Weibel instability, localized in space. In such active wave-particle interaction regions, the seed magnetic field grows exponentially and spreads to larger scales due to the interaction with the underlying stirring motion. Such a self-feeding process might explain magnetogenesis in a variety of astrophysical plasmas, wherever turbulence is present. variety of astrophysical plasmas, wherever turbulence is present.