Bulk Lorentz factor of the wind (Γ_wind) averaged over several spin periods, for each run. Radii are given in units of the light-cylinder radius, represented by the red circle. The fast magnetosonic surface is represented by the dashed green curve. When d_comp > r_fms, a shock of angular aperture ζ (see upper right panel) is established. Otherwise, no shock appears and the whole magnetosphere is slowed down.