Number and positions of magnetic field reversals along the disc radius, for a magnetic field constructed by a superposition of the first three fastest growing eigenfunctions, Q_n(s) with n = 1, 2, 3, for the fiducial choice of parameters shown in Table 1. Left-hand panel: number of the field reversals (colour coded as indicated with the colour bar on the right of the panel) for various ratios of the expansion coefficients C_n/C₁. Middle and right-hand panels: galactocentric distances of the inner and outer reversal, s_rev,1 and s_rev,2 respectively, colour coded with the colour bar to the right of each panel. White colour indicates the absence of the corresponding reversal.