Self-Modulated States of Oscillatory Convection

Oscillatory convection in binary fluid mixtures has been shown to begin as traveling waves which grow exponentially in space and time and reflect the end walls with a reflection coefficient less than unity. This behavior is similar to that of light waves in a laser cavity. When the length of the convection cell is tuned halfway between cavity resonances, completely modulated states are observed which are the beat in space and time of two adjacent K-modes propagating in the same direction. The role of nonlinear effects in selecting these states and the relationship to propagating pulses of convection will be discussed.