Numerical experiments on dynamo action in sheared and rotating turbulence

T. A. Yousef, T. Heinemann, F. Rincon, A. A. Schekochihin, N. Kleeorin, I. Rogachevskii, S. C. Cowley, J. C. McWilliams

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40 Scopus citations

Abstract

Numerical simulations of forced turbulence in elongated shearing boxes are carried out to demonstrate that a nonhelical turbulence in conjunction with a linear shear can give rise to a mean-field dynamo. Exponential growth of magnetic field at scales larger than the outer (forcing) scale of the turbulence is found. Over a range of values of the shearing rate S spanning approximately two orders of magnitude, the growth rate of the magnetic field is proportional to the imposed shear, γ ∝ S, while the characteristic spatial scale of the field is lB ∝ S-1/2. The effect is quite general: earlier results for the nonrotating case by Yousef et al. (2008) are extended to shearing boxes with Keplerian rotation; it is also shown that the shear dynamo mechanism operates both below and above the threshold for the fluctuation dynamo. The apparently generic nature of the shear dynamo effect makes it an attractive object of study for the purpose of understanding the generation of magnetic fields in astrophysical systems.

Original languageEnglish (US)
Pages (from-to)737-749
Number of pages13
JournalAstronomische Nachrichten
Volume329
Issue number7
DOIs
StatePublished - Sep 2008

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Magnetic fields
  • Magnetohydrodynamics (MHD)
  • Turbulence

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    Yousef, T. A., Heinemann, T., Rincon, F., Schekochihin, A. A., Kleeorin, N., Rogachevskii, I., Cowley, S. C., & McWilliams, J. C. (2008). Numerical experiments on dynamo action in sheared and rotating turbulence. Astronomische Nachrichten, 329(7), 737-749. https://doi.org/10.1002/asna.200811018