Multiscale Hall-Magnetohydrodynamic Turbulence in the Solar Wind
Abstract
The spectra of solar wind magnetic fluctuations exhibit a significant power-law steepening at frequencies f>1 Hz. The origin of this multiple scaling is investigated through dispersive Hall magnetohydrodynamics. We perform three-dimensional numerical simulations in the framework of a highly turbulent shell model and show that the large-scale magnetic fluctuations are characterized by a k-5/3-type spectrum that steepens at scales smaller than the ion inertial length di, to k-7/3 if the magnetic energy overtakes the kinetic energy, or to k-11/3 in the opposite case. These results are in agreement both with a heuristic description à la Kolmogorov and with the range of power-law indices found in the solar wind.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2007
- DOI:
- 10.1086/510423
- arXiv:
- arXiv:astro-ph/0610759
- Bibcode:
- 2007ApJ...656..560G
- Keywords:
-
- Magnetohydrodynamics: MHD;
- Sun: Solar Wind;
- Turbulence;
- Astrophysics
- E-Print:
- 7 pages, 4 figures