Temporal evolution of the magnetic and kinetic energies of four unstratified and stratified runs at Re = 5 × 10⁴ and Pm = 1. (a) Nonaxisymmetric magnetic energy, (b) nonaxisymmetric kinetic energy, (c) axisymmetric toroidal (solid lines) and poloidal (dashed lines) magnetic energies as a function of time for the unstratified fiducial dynamo run U0 (black) and the three runs S0, S4, and S9 at 𝒩 = 1, 10, and 20 respectively (see the legend in the middle panel). All the stratified runs are at Pr = 10⁻³. The inset in (a) shows the nonaxisymmetric magnetic energies of runs S0 and S4 on a linear scale. The initial condition of the stratified runs is the steady state solution of run U0 at time t_s = 1241 shown in Fig. 9.