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Non-locality of the Turbulent Electromotive Force

Non-locality of the Turbulent Electromotive Force

Authors :
Bendre, Abhijit B.
Subramanian, Kandaswamy
Publication Year :
2021

Abstract

The generation of large-scale magnetic fields ($\overline{\mathbf{B}}$) in astrophysical systems is driven by the mean turbulent electromotive force ($\overline{{\cal E}}$), the cross correlation between local fluctuations of velocity and magnetic fields. This can depend non-locally on $\overline{\mathbf{B}}$ through a convolution kernel $K_{ij}$. In a new approach to find $K_{ij}$, we directly fit the time series data of $\overline{{\cal E}}$ versus $\overline{\mathbf{B}}$ from a galactic dynamo simulation using singular value decomposition. We calculate the usual turbulent transport coefficients as moments of $K_{ij}$, 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 the present case.<br />Comment: 11 pages, 13 figures

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.2107.10625
Document Type :
Working Paper
Full Text :
https://doi.org/10.1093/mnras/stac339