Structure of Turbulent Radiative Mixing Layers

Turbulent radiative mixing layers (TRMLs), where shear-driven turbulence mixes dense and diffuse gas into rapidly cooling intermediate-temperature gas, are ubiquitous in the interstellar and circumgalactic media. A Reynolds decomposition of 3D simulations shows that a cooling-driven compressive stress creates a pressure dip that sustains a steady inflow of hot gas, and that radiative losses are balanced mainly by enthalpy advection, not turbulent heat flux. Contrary to previous claims, the cooling rate per unit area saturates and becomes independent of box size in the strong-cooling limit.