Traveling waves and spatial variation in the convection of a binary mixture

We report measurements of heat transport and shadowgraph flow visualizations for binary mixture with separation ratio {ψ}apeq2-0.12. Beyond a Hopf bifurcation from pure conduction, a traveling-wave state involving a single frequency develops and consists of a small number of convection rolls concentrated near the sidewall towards which it is moving. Thus about 60% of our cell is left in the pure conduction state. At a slightly larger Rayleigh number, the traveling wave becomes amplitude modulated by a second, lower frequency.