Maximum value of the normalised differential rotation max(ΔΩ/Ω₀) as a function of the contraction timescale as defined in Eq. (12). The main evolution steps are highlighted by coloured dashed lines: the red dashed lines corresponds to the start of the exponential growth phase and orange, to the time at which the instability saturates, thus marking the beginning of the non-linear evolution. Then, blue marks the start of the post-instability evolution and finally, purple denotes the time at which the hydrodynamic steady state is reached. The parameters are Re_c = 1, L_u = 10⁴, E = 10⁻⁴, P_r(N₀/Ω₀)² = 10⁴, and P_m = 10² (run Q10 of Table 1, contraction term in induction equation).