Turbulent radiative diffusion and turbulent Newtonian cooling

Radiation transport plays important roles in stellar atmospheres, but the effects of turbulence are being obscured by other such as stratification. Using radiative hydrodynamic simulations forced turbulence, we determine decay rates sinusoidal large-scale temperature perturbations different wavenumbers optically thick and thin regimes. Increasing wavenumber increases rate both regimes, this effect is much weaker than for usual turbulent diffusion passive scalars, where increase quadratic small wavenumbers. The well described an enhanced Newtonian cooling process limit, which found to show a weak proportional square root wavenumber. In somewhat steeper below energy-carrying levels off toward larger presence typical time comparable turnover time. We observe that takes long reach equilibrium cases, former, retains smaller scale structures longer.