Bonn 2010 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
EP: Fachverband Extraterrestrische Physik
EP 7: Fundamental Physics
EP 7.3: Talk
Tuesday, March 16, 2010, 15:30–15:45, AKM
Surprises in the theory of anisotropic magnetohydrodynamic turbulence — •Wolf-Christian Müller1 and Roland Grappin2 — 1Max-Planck-Institut für Plasmaphysik — 2LUTH, Observatoire de Paris
A new approach toward the analysis of high-Reynolds-number direct numerical simulations of incompressible magnetohydrodynamic (MHD) turbulence subject to a strong mean magnetic field has led to unexpected results: the scaling of one dimensional spectra taken along rays passing through the origin of Fourier space is independent of the rays’ orientation with respect to the mean magnetic field direction; the spectral amplitude variation with respect to the angle between a ray and the mean magnetic field can be eliminated by normalization with an angle-dependent dissipation wavenumber. Thus the anisotropy of MHD turbulence permeated by a strong mean magnetic field does not appear as direction dependent scaling but rather as a direction dependent Reynolds number. These findings invalidate most present phenomenologies for macroscopically anisotropic MHD turbulence which are based on the critical balance argument.