First-principles quasilinear calculation of the nonlocal turbulent electromotive force*

Magnetohydrodynamic (MHD) turbulence can generate coherent magnetic fields through the turbulent electromotive force (EMF) – a process known as the turbulent dynamo. Here we present a calculation of the nonlocal turbulent EMF from first principles without invoking scale separation between the turbulent fluctuations and mean fields, while retaining the self-consistent response of the turbulence to the developing mean field. This is made possible by a mean-field wave kinetics approach, in which the self-consistent coupled evolution of the mean fields and turbulence is derived under the quasilinear approximation using the Weyl calculus. This approach yields novel dynamo solutions, and we report qualitative distinctions between traditional (scale separated and kinematic) and mean-field wave kinetics results.