Continuous nonequilibrium transition driven by heat flow

We discovered an out-of-equilibrium transition in the ideal gas between two walls, divided by inner, adiabatic, movable wall. The system is driven supplying energy directly into volume of gas. At critical heat flux, we have found a continuous to state with low-density, hot on one side wall and dense, cold other side. Molecular dynamic simulations soft-sphere fluid confirm existence interacting system. introduce stationary Helmholtz-like function whose minimum determines stable positions internal This can be used as paradigm transitions states thermodynamic description these states.