Summary of three classes of magnetically dominated accretion flows. For high diffusivity, the model of GL applies, as the field can continuously slip through the disk and not be constantly wrapped up. For intermediate diffusivity, the model of LRBK applies as the field is wrapped up until it opens, but steady solutions are possible if the diffusion velocity remains greater than the peak expected radial velocity of the inner edge of the disk. For low diffusivity, the model of Goodson et al. (1997) applies, as the radial velocity exceeds the diffusion velocity and the flow must (for strong field cases) be unsteady.
