Wave diagnostic diagrams, also knows as k_h − ω diagrams, for the HD_256 (left) and MHD_256 (right) simulations at z = 8.5 Mm. The sampling rate and grid cell size are Δt_s = 0.5 s and Δx = 42.0 km, respectively. The strength of the signal is color-coded. The dispersion relations for sound waves and surface modes are shown in dashed and dotted lines, respectively. The Brunt–Väisälä frequency is depicted by a dash-dotted line.