Dynamo and Alfven eect in MHD turbulence

This extended abstract reports a spectral relation between residual and total energy, ERk = jEMk EKk j and Ek = EKk + EMk respectively, as well as the in uence of an imposed mean magnetic eld on the spectra. The proposed physical picture, which is conrmed by accompanying direct numerical simulations, embraces two-dimensional MHD turbulence, globally isotropic three-dimensional systems as well as turbulence permeated by a strong mean magnetic eld. The results have direct implications on the current understanding of the energy cascade in MHD turbulence. In the following reference is made to two high-resolution pseudospectral direct numerical simula-tions of incompressible MHD turbulence which we regard as paradigms for isotropic (I) and anisotropic (II) MHD turbulence. The dimensionless MHD equations @t! = r [v ! b (r b)] + ! (1