  We analyze the configuration of a thin rotating accretion disk, which is
embedded in a magnetic field inducing a backreaction in the gravitating plasma.
The aim of this study is to determine the conditions under which the gaseous
accretion model of Shakura can be reconciled with the magneto-hydrodynamical
picture requested to trigger the underlying turbulent behavior. We focus our
attention to the generalized Ohm equation in order to understand if the plasma
backreaction is able to provide the proper toroidal current, allowing a
non-zero infalling velocity. In the limit of linear plasma backreaction, this
analysis shows how the Shakura profile of accretion turns out to be
inconsistent. In particular, comparing the azimuthal and the generalized Ohm
equilibrium equations, we argue that it is not possible to maintain a constant
rate of accretion. A non-stationary scenario for the disk configuration is then
outlined and it results into a transient process which is however associated to
a vanishing accretion rate.
