Third-order Elsasser moments in axisymmetric MHD turbulence

Incompressible MHD turbulence is investigated under the presence of a uniform magnetic field B-0. Such a situation is described in the correlation space by a divergence relation which expresses the statistical conservation of the Elsasser energy flux through the inertial range. The ansatz is made that the development of anisotropy, observed when B-0 is strong enough, implies a foliation of space correlation. A direct consequence is the possibility to derive a vectorial law for third-order Elsasser moments which is parametrized by the intensity of anisotropy. We use the so-called critical balance assumption to fix this parameter and find a unique expression. (c) 2010 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.