Weakly Nonlinear Traveling-Wave Convection

We have performed experiments on traveling-wave convection in a rectangular container for small, negative values of the separation ratio: PSI = -0.043 to -0.011. Just above onset, the linear, counterpropagating traveling- wave state evolves into a nonlinear state in which the dynamics appear to be due to competition between left- and right-traveling waves. The typical result of this is that the traveling waves are confined to small regions whose position jumps back and forth between the two ends of the cell, leading to a show, aperiodic modulation in the traveling-wave signal. This talk will be given in conjunction with a theoretical talk by M.C. Cross of Caltech.