Comparison of (a) the toroidal protostellar magnetic field component B_φ as stated in Eq. (8), (b) the midplane gas temperature T_gas, 0, and (c) the surface density Σ for the different stationary initial models in Table 1 of varying protostellar magnetic field strengths, ranging from B_⋆ = 1.5 kG to 5 kG. The MRI active zone starts at little over 1400 K for our choice of T_active = 1530 K and T_width = 50 K. The vertical dashed lines denote the position of the stellar radius R_⋆ and the initial corotation radius r_cor, init.