Normalized degree of polarization as a function of wavelength illustrated for a one-layer a), two-layer b), three-layer c) system with characteristic profiles for DFR only (black solid), IFD only (blue dashed), and DFR with IFD (red dotted). A total isotropic turbulent magnetic field strength of 5 μG together with a total regular magnetic field strength also of 5 μG has been used in the disk and in the halo. The parameters of n_e,n_cr,L,d,α used in the construction of these plots are the same as those for the example bin of Sect. 6 and their values are reported in the bottom panel of Table 1.