a)–d) Contours of equal reduced chi-square values for regular magnetic field strengths in disk and halo in a two-layer model for each of the four rings. The best-fit DAIHI model, denoted by ★, is composed of regular, isotropic turbulent and anisotropic turbulent disk and halo magnetic fields with respective minimum reduced chi-square () values and field strengths presented in Table 4. The dashed, solid, and dotted contours represent 10,50, and 100 percent increases in the value, respectively.