We are particularly interested in the difference between the coarsening process for a system approaching an equilibrium thermodynamic state, and one approaching a state that is steady but far from equilibrium such as Rayleigh-Benard convection.
Here are two movies showing domain coarsening in numerical simulations of models of Rayleigh-Benard convection. The frames show the local orientaion of the stripes using a rainbow color plot to show the angle of the stripes (0 to 180 degrees) to the vertical on the screen. The scale ranges from red (vertical stripes) through yellow and green to light blue (horizontal stripes) through purple back to red. A domain of straight parallel stripes will be a uniform color. The movies are on a loagarithmic time scale, i.e. each successive frame is at a time that is a fixed multiple (here about 1.4) of the time of the previous frame, rather than an additive time later. This is because we find that the scale of the domains grows as a power law.
The first movie is for the Swift-Hohenberg model, which although used to describe convection could also be used to describe a thermodynamic phase (a smectic liquid crystal); the second is a "non-potential" model which intrinsically describes a state far from equilibrium.
The research leading to the results presented here was supported by the NSF.
Non-Potential Model (Click for 1MB mpeg movie)