A A Schekochihin et al 2002 New J. Phys. 4 84 doi:10.1088/1367-2630/4/1/384
A model of nonlinear evolution and saturation of the turbulent MHD dynamo
Focus on Turbulence in Magnetized PlasmasA A Schekochihin1, S C Cowley1, G W Hammett1,3, J L Maron1,4 and J C McWilliams2
Show affiliationsPart of Focus on Turbulence in Magnetized Plasmas
The growth and saturation of magnetic field in conducting turbulent media with large magnetic Prandtl numbers are investigated. This regime is very common in low-density hot astrophysical plasmas. During the early (kinematic) stage, weak magnetic fluctuations grow exponentially and concentrate at the resistive scale, which lies far below the hydrodynamic viscous scale. The evolution becomes nonlinear when the magnetic energy is comparable to the kinetic energy of the viscous-scale eddies. A physical picture of the ensuing nonlinear evolution of the MHD dynamo is proposed. Phenomenological considerations are supplemented with a simple Fokker-Planck model of the nonlinear evolution of the magnetic-energy spectrum. It is found that, while the shift of the bulk of the magnetic energy from the subviscous scales to the velocity scales may be possible, it occurs very slowly - at the resistive, rather than dynamical, timescale (for galaxies, this means that the generation of large-scale magnetic fields cannot be explained by this mechanism). The role of Alfvénic motions and the implications for the fully developed isotropic MHD turbulence are discussed.
- PACS
-
47.65.-d Magnetohydrodynamics and electrohydrodynamics
52.65.Ff Fokker-Planck and Vlasov equation
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
- Subjects
- Dates
-
Issue 1 (October 2002)
Received 24 July 2002, in final form 26 September 2002
Published 30 October 2002
-
A model of nonlinear evolution and saturation of the turbulent MHD dynamo
A A Schekochihin et al 2002 New J. Phys. 4 84
-
Search for Weakly Interacting Massive Particles with CDMS and XENON
Elena Aprile et al 2007 J. Phys.: Conf. Ser. 60 58
-
Simulation of biological flow and transport in complex geometries using embedded boundary/volume-of-fluid methods
David Trebotich 2007 J. Phys.: Conf. Ser. 78 012076
-
Short- and long-range correlated motion observed in colloidal glasses and liquids
Eric R Weeks et al 2007 J. Phys.: Condens. Matter 19 205131
-
Structure and magnetism of ultra-thin chromium layers on W(110)
B Santos et al 2008 New J. Phys. 10 013005
-
Control of colloids with gravity, temperature gradients, and electric fields
Matt Sullivan et al 2003 J. Phys.: Condens. Matter 15 S11
-
Data management on the fusion computational pipeline
S Klasky et al 2005 J. Phys.: Conf. Ser. 16 510
-
Analytic Light Curves for Planetary Transit Searches
Kaisey Mandel and Eric Agol 2002 ApJ 580 L171
-
Nanoemulsions: formation, structure, and physical properties
T G Mason et al 2006 J. Phys.: Condens. Matter 18 R635
-
Thermal gradient induced actuation in double-walled carbon nanotubes
Quan-Wen Hou et al 2009 Nanotechnology 20 495503
Related review articles
What's this?- Plasmas as metamaterials: a review
- Investigation of intermittency and generalized self-similarity of turbulent boundary layers in laboratory and magnetospheric plasmas: towards a quantitative definition of plasma transport features
- Major minority: energetic particles in fusion plasmas