Left: evolution of total magnetic energy normalized to the initial value, for different initial magnetic-field strengths: B _6.5 (continuous black line), B _5.0 (dashed red line), B _3.5 (long-dashed blue line), and B _1.5 (dot-dashed magenta line). Middle: evolution of poloidal and toroidal magnetic energies normalized to the initial total magnetic energy (log scale) for B _6.5, B _1.5. Right: ratio of toroidal and poloidal magnetic energies vs. time for the same collection of simulations shown in the left panel.