Dependence of the kinetic and magnetic energy densities on Re. In the top panel, we show $E_{\mathrm{kin}}^{\mathrm{tot}}$ (black), which is composed of $E_{\mathrm{kin}}^{\mathrm{flu}}$ (red), $E_{\mathrm{kin}}^{\mathrm{dif}}$ (blue), and $E_{\mathrm{kin}}^{\mathrm{mer}}$ (purple) for H runs (dashed), M runs (solid), and S runs (dotted). In the bottom panel, we show $E_{\mathrm{mag}}^{\mathrm{tot}}$ (black) composed of $E_{\mathrm{mag}}^{\mathrm{flu}}$ (red), $E_{\mathrm{mag}}^{\mathrm{tor}}$ (blue), and $E_{\mathrm{mag}}^{\mathrm{pol}}$ (purple). $E_{\mathrm{mag}}^{\mathrm{M}}=E_{\mathrm{mag}}^{\mathrm{tor}}+E_{\mathrm{mag}}^{\mathrm{pol}}$ is the energy density of the mean magnetic field (yellow) (see Eqs. (8)–(11) for definitions). The lower mean-field energy densities for Re ∼ 530 indicate Run 4M2, which has been started from Run S4 and is possibly not yet saturated, hence the bifurcation.