Solitons and the commensurate-incommensurate transition in a convecting nematic fluid

Abstract

Quasiperiodic (incommensurate) patterns consisting of an array of solitons are found in a convecting nematic fluid subjected to spatially periodic forcing. The solitons are regions of local compression of the convective rolls and are well described by solutions to the sine-Gordon equation. The commensurate-incommensurate transition is continuous for weak forcing, but becomes discontinuous as the forcing amplitude increases. This behavior indicates the existence of a tricritical point on the phase transition line.