Variation of the escaping fraction (f_e) and anisotropic fraction (f_a) with the coronal optical depth (τ). The equilibrium solutions are computed using the same reference parameter set as in Fig. 3. To facilitate comparison, the theoretical expectation for f_e, given by exp(−2τ), is also shown. The factor of 2 arises because τ in MONK is defined as the vertical optical depth from the mid-plane of the slab to its surface.