Angular velocity Ω (red), toroidal magnetic component B_ϕ (blue), and magnetic viscosity η (green) as a function of the Lagrangian mass coordinate at eight different moments in time in test calculations of a 1.5 M_⊙ main-sequence stellar model, using different assumptions for magnetic and viscous dissipation. Left panel: results for no dissipation, results with dissipation only due to hydrodynamic instabilities are shown in the middle, and results with hydrodynamic dissipation and Pitts–Tayler instabilities are shown in the right panel. For this stellar model the wave-crossing time is t_wc = 1.71 × 10⁹ s. The top seven plots of each panel cover about two wave-crossing times (3.4 × 10⁹ s) with five snapshots per plot, one every 10⁸ s, for the period given in the top right corner of each plot. In the bottom row of plots, results after about six wave-crossing times are shown, i.e., from 9.9 × 10⁹ s to 10.3 × 10⁹ s. The temporal evolution is available as an online movie.