Transient localized states in 2D binary liquid convection.

We report an experimental study of the onset of convection in ethanol-water mixtures con ned in a circular cell of radial aspect ratio 11.6. The initial bifurcation was to radial traveling waves; however, the linear state typically gave way to a nonlinear one in which convection alternately focused along one cell diameter and then another roughly perpendicular to the rst. After a number of cycles, this state frequently collapsed to a localized pulse of traveling-wave convection very similar to those observed in 1d geometries. The pulses we observed either decayed back to pure conduction or grew to ll or nearly ll the cell.