Hyperdiffusion in nonlinear large- and small-scale turbulent dynamos.

  title={Hyperdiffusion in nonlinear large- and small-scale turbulent dynamos.},
  author={Kandaswamy Subramanian},
  journal={Physical review letters},
  volume={90 24},
  • K. Subramanian
  • Published 2 March 2003
  • Physics, Medicine
  • Physical review letters
The generation of large-scale magnetic fields is generically accompanied by the more rapid growth of small-scale fields. The growing Lorentz force due to these fields backreacts on the turbulence to saturate the mean-field and small-scale dynamos. For the mean-field dynamo, in a quasilinear treatment of this saturation, it is generally thought that, while the alpha effect gets renormalized and suppressed by nonlinear effects, the turbulent diffusion is left unchanged. We show here that this is… Expand

Topics from this paper

Simulations of the Small-Scale Turbulent Dynamo
We report the results of an extensive numerical study of the small-scale turbulent dynamo. The primary focus is on the case of large magnetic Prandtl numbers Prm, which is relevant for hotExpand
On the resilience of helical magnetic fields to turbulent diffusion and the astrophysical implications
The extent to which large scale magnetic fields are susceptible to turbulent diffusion is important for interpreting the need for in situ large scale dynamos in astrophysics and for observationallyExpand
Large scale magnetic fields and coherent structures in nonuniform unmagnetized plasma
The properties of streamers and zonal magnetic structures in magnetic electron drift mode turbulence are investigated. The stability of such large scale structures is investigated in the kinetic andExpand
The small-scale dynamo in a spectral representation
ABSTRACT In this paper, we study the correlation functions for magnetic energy and magnetic helicity generated by a small-scale dynamo mechanism in a mirror-asymmetric and isotropic turbulentExpand
Saturation mechanism of the fluctuation dynamo at PrM ≥ 1
The presence of magnetic fields in many astrophysical objects is due to dynamo action, whereby a part of the kinetic energy is converted into magnetic energy. A turbulent dynamo that producesExpand
Seed magnetic fields in turbulent small-scale dynamos
Magnetic fields in galaxies and galaxy clusters are amplified from a very weak seed value to the observed $\mu{\rm G}$ strengths by the turbulent dynamo. The seed magnetic field can be of primordialExpand
Fluctuation dynamo based on magnetic reconnections
We develop a new model of the fluctuation dynamo in which the magnetic field is confined to thin flux ropes advected by a multi-scale flow which models turbulence. Magnetic dissipation occurs onlyExpand
Magnetic helicity generation in the frame of Kazantsev model
Abstract Using a magnetic dynamo model, suggested by Kazantsev (J. Exp. Theor. Phys. 1968, vol. 26, p. 1031), we study the small-scale helicity generation in a turbulent electrically conductingExpand
The turbulent dynamo
  • S. Tobias
  • Physics, Medicine
  • Journal of Fluid Mechanics
  • 2021
It is argued that progress in dynamo theory will be made in the future by utilising and advancing some of the current breakthroughs in neutral fluid turbulence such as those in transition, self-sustaining processes, turbulence/mean-flow interaction, statistical and data-driven methods and maintenance and loss of balance. Expand
Evolving turbulence and magnetic fields in galaxy clusters
We discuss, using simple analytical models and magnetohydrodynamic (MHD) simulations, the origin and parameters of turbulence and magnetic fields in galaxy clusters. Any pre-existing tangled magneticExpand


The Almighty Chance
This book is about the importance of random phenomena occurring in nature. Cases are selected in which randomness is most important or crucial, such as Brownian motion, certain reactions in PhysicalExpand
Magnetic Field Generation in Electrically Conducting Fluids
H K Moffatt 1983 Cambridge: Cambridge University Press x + 343 pp price £12.50 (paperback) ISBN 0 521 27583 0 Professor Moffatt has written a careful account of a subject of fundamental importanceExpand
however (for it was the literal soul of the life of the Redeemer, John xv. io), is the peculiar token of fellowship with the Redeemer. That love to God (what is meant here is not God’s love to men)Expand
  • J., 550, 824
  • 2001
astro-ph/9708216; MNRAS
  • 294, 718 (1998); K. Subramanian, Phys. Rev. Lett., 83, 2957 (1999); A. Brandenburg and K. Subramanian, Astron. & Astrophys., 361, L33
  • 2000
  • Phys. JETP, 26, 1031 (1968); Ya. B. Zeldovich, A. A. Ruzmaikin and D. D. Sokoloff, The almighty chance, World Scientific, Singapore (1990); S. Vainshtein and L. L. Kichatinov, J. Fluid. Mech., 168, 73 (1986); R. M. Kulsrud, and S.W. Anderson, Astrophys. J., 396, 606 (1992); A. Schekochihin, S. Cowle
  • 2001
  • Rev. Lett., 72, 1651 (1994); K. Avinash, Phys. Fluids B, 3, 2150
  • 1991
Magnetic fields in Astrophysics, Gordon and Breach, New York
  • Cosmic magnetic fields,
  • 1978
  • & Astrophys., 361, L5 (2000); 387, 453 (2002); E. Blackman & A. Brandenburg, Astrophys. J., 579, 359 (2002); K. Subramanian, Bull. Astr. Soc. India, 30, 715
  • 2002
  • Lett. A., 259, 232 (1999); A. Schekochihin, S. Cowley, G. W. Hammett, J. Maron, J. C. McWilliams, New Jour. of Phys., 4, 84
  • 2002