Left column row: example maps (from top to bottom: total intensity I_m on a logarithmic scale, Stokes Q_m, and Stokes U_m) from simulation A (see Sect. 5 and Table 3). Right column: corresponding power spectra. The grey points represent the two-dimensional power spectra, while the black dots represent the azimuthal averages in Fourier space in a set of wavenumber bins, and the blue line is a power-law fit to the black points.