Temporal evolution and dynamical decomposition of the lower branch solutions LB_1m (left) and LB_2m (right). LB_1m is shown for Re = 100, Rm = 900 and LB_2m for Re = 908, Rm = 3033. From top to bottom, axisymmetric field , axisymmetric EMF (ℰ_0x,−ℰ_0y) and total energy (integrated over all k_z) of each shearing wave packet (k_y = 2π/L_y) as a function of time (two cycle periods are represented). The rainbow colours and ℓ in the bottom plots represent successive shearing wave packets (see Sects. 2–4). The 3D visualizations show isosurfaces of B_y at t = 0 and t = T₀/ 4, where T₀ is the period of the corresponding cycle. Videos showing the total B_y and the poloidal velocity streamlines for SN_1m and SN_2m are available online.