Temporal development of the jets during spin-up. We show the kinetic energy of zonal flows (a) and poloidal flows (b, mostly convection), shell-averaged rms Reynolds stresses (c and d), and the surface jet profile (e). See Eqs. (35) and (36) for definitions of the spatial averages of the Reynolds stresses and correlation coefficients. This run was performed using a convective initial condition without jets. The duration of a convective turnover time is about 10⁻³ τ_visc. We show results for the spatially resolved Reynolds stresses and the energy transfer to the jets during the intervals marked as gray bands in Figs. 13 and 14.