Comparison of the magnetic flux and the tilt angle evolution for uniform twist models (h = 0 and g = 0) with N_t, 0 = 0.2 and N_t, 0 = 0.7. (a) Evolution of the magnetic flux, F_z (continuous lines), the azimuthal flux, (dashed lines), and the axial flux, (green-continuous line) for the models with N_t, 0 = 0.2 (black) and N_t, 0 = 0.7 (red). The vertical continuous lines (with the same black and red colours) show respectively the time step in which each model reaches its maximum F_z flux. The black-dashed vertical line indicates the time step in which is maximum. All fluxes are normalised to the maximum . (b)–(c) Evolution of the tilt angle for models with (b) N_t, 0 = 0.2 and (c) N_t, 0 = 0.7. The black and red lines show the tilt angle estimations of ϕ_a and ϕ_c (see inset), respectively. The red-shaded areas correspond to the values of ϕ_c computed for p within the interval [−1, 1]. The associated movies are available online (fig5_b.avi and fig5_c.avi).