Stokes Q polarization maps obtained for filaments (left) and sheets (right) with different parameter values for the stochastic component of the magnetic field B_sto. The component amplitude (n_i) is constant in column and increases from left to right, and the correlation length (n_c) is constant in rows and increases from top to bottom. The circular regions, here centered on the north Galactic pole, have an angular radius of 12.53°. The shape parameters, including those controlling the wiggles, are the same as in Fig. 3 and are kept fixed between panels. All maps share the same color scale.