title: Magnetic-field generation in helical turbulence.
abstract: We investigate analytically the amplification of a weak magnetic field in a homogeneous and isotropic turbulent flow lacking reflectional symmetry (helical turbulence). We propose that the spectral distributions of magnetic energy and magnetic helicity can be found as eigenmodes of a self-adjoint, Schrödinger-type system of evolution equations. We argue that large-scale and small-scale magnetic fluctuations cannot be effectively separated, and that the conventional model alpha is, in general, not an adequate description of the large-scale dynamo mechanism. As a consequence, the correct numerical modeling of such processes should resolve magnetic fluctuations down to the very small, resistive scales.
authors.affiliation: Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Boldyrev
authors.forename: Fausto
authors.initials: F
authors.lastname: Cattaneo
authors.forename: Robert
authors.initials: R
authors.lastname: Rosner