The large-scale magnetic field in protoplanetary discs

Séminaire IPAG de Jérôme Guilet (MPA), jeudi 16 octobre 2014 à 11h00, IPAG seminar room

If a large-scale poloidal magnetic field is present in protoplanetary discs, it could have important dynamical consequences : the launching of a jet or a wind, a more vigorous MHD turbulence in the outer parts of the disc, or the quenching of turbulence at smaller radii. It could also influence the migration of protoplanets in the disc. The structure and strength of the magnetic field is, however, poorly known from both observational and theoretical points of view. I will describe a theoretical model of the evolution of the large-scale magnetic field in a protoplanetary disc : first a local approach enabling to compute the transport of magnetic flux, and its application to a global disc model. I will finally discuss the implications of these results for the evolution of protoplanetary discs and for the formation of powerful jets as observed in T-Tauri star systems.