Magnetic energy spectrum produced by turbulent dynamo: effect of time irreversibility [CL]

http://arxiv.org/abs/2112.05736


We consider the kinematic stage of evolution of magnetic field advected by turbulent hydrodynamic flow. We use a generalization of the Kazantsev-Kraichnan model to investigate time irreversible flows. In the viscous range of scales, the infinite-time limit of the spectrum is a power law but its slope is more flat than that predicted by Kazantsev model. This result agrees with numerical simulations. At early stages, the rate of magnetic energy growth is slower than that in the time-symmetric case. We show that for high magnetic Prandtl turbulent plasma, the formation of the spectrum shape takes very long time and may never happen because of the nonlinearity. A finite-time ansatz for the spectrum shape more accurate than a power law is proposed.

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A. Kopyev, A. Il’yn, V. Sirota, et. al.
Mon, 13 Dec 21
51/70

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