Global Turbulent Solar Convection: A Numerical Path Investigating Key Force Balances in the Context of the Convective Conundrum

Understanding solar turbulent convection and its influence on differential rotation has been a challenge over the past two decades. Current models often overestimate giant convection cells' amplitude, leading to an effective Rossby number (Ro) too large and a shift toward an antisolar rotation regime. This convective conundrum underscores the need for improved comprehension of solar convective dynamics. We propose a numerical experiment in the parameter space that controls Ro while increasing the Reynolds number (Re) and maintaining solar parameters. By controlling the Nusselt number (Nu), we limit the energy transport by convection while reducing viscous dissipation. This approach enabled us to construct a Sun-like rotating model (SBR97n035) with strong turbulence (Re ∼ 800) that exhibits prograde equatorial rotation and aligns with observational data from helioseismology. We compare this model with an antisolar rotating counterpart and provide an in-depth spectral analysis to investigate the changes in convective dynamics. We also find the appearance of vorticity rings near the poles, whose existence on the Sun could be probed in the future. The Sun-like model shows reduced buoyancy over the spectrum, as well as an extended quasi-geostrophic equilibrium toward smaller scales. This promotes a Coriolis–inertia (CI) balance rather than a Coriolis–inertia–Archimedes (CIA) balance, in order to favor the establishment of a prograde equator. The presence of convective columns in the bulk of the convection zone, with limited surface manifestations, also hints at such structures potentially occurring in the Sun.