On the turbulent energy cascade in anisotropic magnetohydrodynamic turbulenceV. Carbone1, 2, L. Sorriso-Valvo2 and R. Marino1, 3
1 Dipartimento di Fisica, Università della Calabria - Ponte P. Bucci, Cubo 31C, 87036 Rende (CS), Italy, EU
2 Liquid Crystal Laboratory (CNR) - Rende (CS), Italy, EU
3 University of Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur - B.P. 4229, 06304 Nice Cedex 4, France, EU
received 21 May 2009; accepted in final form 9 October 2009; published October 2009
published online 5 November 2009
The problem of the occurrence of an energy cascade for Alfvénic turbulence in solar wind plasmas was historically addressed by using phenomenological arguments based to the sweeping of Alfvénic fluctuations by the large-scale magnetic field and the anisotropy of the cascade in wave vectors space. Here, this paradox is reviewed through the formal derivation of a Yaglom relation from the anisotropic magnetohydrodynamic equation. The Yaglom relation involves a third-order moment calculated from velocity and magnetic fields and involving both Elsässer vector fields, and is particularly useful to be used as far as spacecraft obervations of turbulence are concerned.
52.30.Cv - Magnetohydrodynamics (including electron magnetohydrodynamics).
94.05.Lk - Turbulence.
96.50.Tf - Interplanetary physics: MHD waves; plasma waves, turbulence.
© EPLA 2009