Equatorial power spectra of longitudinal velocity v_ϕ. (a) The power spectrum near the top boundary r = 0.95 R_⊙. The power is normalized at each m. The spectrum is computed in a frame rotating at Ω₀/2π = 431.3 nHz (the rotation rate of the radiative interior). The blue line represents the advective speed by the local differential rotation, m[Ω(0.95R_⊙,π/2)−Ω₀]. Overplotted in red is the dispersion relation of the columnar convective modes from the linear eigenmode calculation. (b) Same equatorial power spectrum as in (a), but at fixed azimuthal order m = 8 as a function of depth. The blue line is again the local advection frequency and the red line is the eigenfrequency from the linear analysis.