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arXiv · 1708.06120

Amplification of large-scale magnetic field in nonhelical magnetohydrodynamics

Rohit Kumar·Mahendra K. Verma
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Abstract

It is typically assumed that the kinetic and magnetic helicities play a crucial role in the growth of large-scale dynamo. In this paper we demonstrate that helicity is not essential for the amplification of large-scale magnetic field. For this purpose, we perform nonhelical magnetohydrodynamic (MHD) simulation, and show that the large-scale magnetic field can grow in nonhelical MHD when random external forcing is employed at scale $1/10$ the box size. The energy fluxes and shell-to-shell transfer rates computed using the numerical data show that the large-scale magnetic energy grows due to the energy transfers from the velocity field at the forcing scales.

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Rohit Kumar, Mahendra K. Verma. 2017-08-21. Amplification of large-scale magnetic field in nonhelical magnetohydrodynamics. https://doi.org/10.1063/1.4997779

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