Characterizing the MRI-driven turbulent transport in astrophysical disks

Since 1990, the magneto-rotational instability (MRI) has been widely recognized as the most promising process to provide a turbulent transport satisfying the observational constraints. Although nearly all disk models make reference to this instability as the source of turbulence, some important aspects of the MRI-driven turbulent state and related effective viscous and resistive transport efficiencies are not well-known. I present recent results on this issue, based on local simulations of the MRI performed with a new MHD spectral code. These results focus on the role of finite (microscopic) resistivity and viscosity on the large-scale turbulent Reynolds and Maxwell stresses, and on the mean large scale electromotive force. This work is expected to give better constraints on turbulent transport, in particular on turbulent resistivity and its anisotropy, which are critically needed for future large scale disk/jets models and simulations.