Non-equilibrium stratification in supercritical CO 2 (opens in new tab)

Supercritical matter is commonly described as a continuous phase lacking sharp boundaries between liquid-like and gas-like regions. Under non-equilibrium conditions, however, this picture may fail. Here, we experimentally investigate non-equilibrium density fluctuations in supercritical carbon dioxide (CO2) subjected to a stabilizing temperature gradient. Using shadowgraphy, we observe the spontaneous emergence of fluid stratification into distinct layers separated by transition regions, acro...