title: Magnetic reversals in a simple model of magnetohydrodynamics.
abstract: We study a simple magnetohydrodynamical approach in which hydrodynamics and MHD turbulence are coupled in a shell model, with given dynamo constraints in the large scales. We consider the case of a low Prandtl number fluid for which the inertial range of the velocity field is much wider than that of the magnetic field. Random reversals of the magnetic field are observed and it shown that the magnetic field has a nontrivial evolution--linked to the nature of the hydrodynamics turbulence.
authors.affiliation: Dipartimento di Fisica and INFN, Università Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Benzi
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Pinton