Upper panel: density structure for an example snapshot from the MHD simulations for HD 191612, as performed by Sundqvist et al. (2012). Lower panel: azimuthal average of the MHD simulations. In both figures, the density has been normalized by a typical down-flow density, , with Ṁ_B= 0 from Table 5, and v_esc ≈ 800 km s⁻¹ the photospheric escape velocity. The velocity field is displayed by arrows, with the length of the velocity vectors limited to 0.5 v_esc. We additionally show the dipole magnetic field of the ADM models used in Sect. 6.2 (solid lines, and thick solid line for R_A = 2.7R_∗). The corresponding magnetic axis is aligned with the z-axis. The grey colour corresponds to densities outside the range indicated on the right.