Penetrative Turbulent Compressible Convection

The outer third of the Sun's radius is convectively
unstable. Turbulent motions from this region known as Penetrative
Turbulent Compressible Convection (PTCC) may penetrate into stable
layers below, mixing temperature, momentum and chemicals.The outer
third of the Sun's radius is convectively unstable. Very turbulent
motions from this zone may penetrate into stable layers below, mixing
temperature, momentum and chemicals significantly there. In an attempt
to understand such processes, researchers at Colorado University
created a simple model of this situation.

Shown here is a visualization of enstrophy (vorticity squared) from
such a simulation of penetrative turbulent convection in a
compressible ideal gas (PTCC). The physical domain is divided into two
halves, where the upper is unstably stratified and the lower is stably
stratified, enforced by an imposed thermal conductivity
profile. Intense enstrophy structures (bright yellow, opaque) can be
seen in the convection, including strong, coherent, downflowing
plumes, which can penetrate into the lower stable half of the
box.