Stellar convection is a non-local process responsible for the transport of heat and chemical species. It can lead to enhanced mixing
through convective overshooting and excitation of internal gravity waves (IGWs) at convective boundaries. The relationship
between these processes is still not well understood and requires global ...
Stellar convection is a non-local process responsible for the transport of heat and chemical species. It can lead to enhanced mixing
through convective overshooting and excitation of internal gravity waves (IGWs) at convective boundaries. The relationship
between these processes is still not well understood and requires global hydrodynamic simulations to capture the important
large-scale dynamics. The steep stratification in stellar interiors suggests that the radial extent of such simulations can affect the
convection dynamics, the IGWs in the stably stratified radiative zone, and the depth of the overshooting layer. We investigate these
effects using 2D global simulations performed with the fully compressible stellar hydrodynamics code MUSIC. We compare
eight different radial truncations of the same solar-like stellar model evolved over approximately 400 convective turnover
times. We find that the location of the inner boundary has an insignificant effect on the convection dynamics, the convective
overshooting, and the travelling IGWs. We relate this to the background conditions at the lower convective boundary which are
unaffected by the truncation, as long as a significantly deep radiative layer is included in the simulation domain. However, we find
that extending the outer boundary by only a few per cent of the stellar radius significantly increases the velocity and temperature
perturbations in the convection zone, the overshooting depth, the power and the spectral slope of the IGWs. The effect is related
to the background conditions at the outer boundary, which are determined in essence by the hydrostatic stratification and the
given luminosity.