Non-locality of the turbulent electromotive force

The generation of large-scale magnetic fields (B̄) in astrophysical systems is driven by the mean turbulent electromotive force (E), the cross-correlation between local fluctuations of velocity and magnetic fields. This can depend non-locally on B̄ through a convolution kernel Kij. In a new approach to find Kij, we directly fit the time-series data of E versus B̄ from a galactic dynamo simulation using singular value decomposition. We calculate the usual turbulent transport coefficients as moments of Kij, and show the importance of including non-locality over eddy length-scales to fully capture their amplitudes and that higher order corrections to the standard transport coefficients are small in this case.