Change of the maximum height of field lines rooted in the photosphere at time t = 600 s compared to their initial height, Δh = h(t = 600)−h(t = 0). Panels from left to right show the result for the simulations initialized at t₋₂₄, t₋₁₂ and the reference time, respectively, using Ω_opt. The orange solid (black dashed) contour indicates field lines of lengths 100 (200) Mm. The gray scale shows the vertical component of photospheric magnetic field saturated at ±0.1 T.