Lack of universality in MHD turbulence, and the possible emergence of a new paradigm?
Abstract
We review some of the recent results obtained in MHD turbulence, as encountered in many astrophysical objects. We focus attention on the lack of universality in such flows, including in the simplest case (no externally imposed magnetic field, no forcing, unit magnetic Prandtl number). Several parameters can foster such a breakdown of classical Kolmogorov scaling, such as the presence of velocity-magnetic field correlations, or of magnetic helicity and the role of the interplay between nonlinear eddies and Alfvén waves. A link with avalanche processes is also discussed. These findings have led to the conjecture of the emergence of a new paradigm for MHD turbulence, as a possibly unsettled competition between several dynamical phenomena.
- Publication:
-
Astrophysical Dynamics: From Stars to Galaxies
- Pub Date:
- August 2011
- DOI:
- 10.1017/S174392131101773X
- Bibcode:
- 2011IAUS..271..304P
- Keywords:
-
- turbulence;
- magnetic fields;
- (magnetohydrodynamics:) MHD;
- waves;
- Sun: flares;
- (Sun:) solar wind;
- stars: activity;
- ISM: magnetic fields