H i/H ii boundaries in the wind compression model (Sect. 2) at the vicinity of the hot star (solid thick circle). They were calculated according to Eq. (13) for a = 20, 50, and 100 km s^-1, displayed at the top, middle, and bottom row of panels, respectively, with fixed v_∞ = 2000 km s^-1 and β = 1.7. The rotational velocities, v_rot, are in  km s^-1. The boundaries are labelled by the corresponding parameter X. The neutral H i zone extends from the boundary in directions outside the star. The remainder part of the wind is ionized. Boundaries are axially symmetric with respect to the spin axis of the WD (the black circle), assumed to be perpendicular to the orbital plane. Distances are in units of the WD radius.