(a) Kinetic energy spectra, ${\displaystyle \sum _{k_y}}{\widehat{e}}_{\mathrm{kin}}$, as functions of longitudinal wavenumber k_x in the middle convection zone (z = 1.1 H_r) for HD cases. Different colors correspond to different Co_*. The dotted black line shows a $k_x^{-5/3}$ power law. (b) Same kinetic energy spectra as panel (a) but for MHD cases. Dotted curves show the magnetic energy spectra, ${\displaystyle \sum _{k_y}}{\widehat{e}}_{\mathrm{mag}}$, at the same depth. (c) Mean wavenumber, ${\overline{k}}_{x,\mathrm{mean}}$, defined by Eq. (29) as functions of Co_*. The blue and red colors correspond to the HD and MHD cases, respectively. The dotted gray lines show $\propto {\mathrm{Co}}_{\ast }^{3/5}$ and $\propto {\mathrm{Co}}_{\ast }^{1/3}$ dependences theoretically expected from the CIA and MAC balances. The inset shows the wavenumbers where the kinetic energy spectra peak, ${\overline{k}}_{x,\mathrm{peak}}$.