Convergence with respect to grid resolution for two representative CZ–RZ mixed modes with strong spatial variations. The top and bottom rows show the results for the modes labelled 5. (b) and 4. (b) in Fig. 10, respectively. Panel 1: Mode structures for various radial resolutions (N_r) with fixed latitudinal resolution N_θ = 60. Panel 2: Mode structures for various N_θ with fixed N_r = 180. Surface and radial variations of the modes are represented in panels (a) and (b), respectively, in the same way as in Fig. 10.