CHAOTIC INSTABILITIES IN SMECTIC-C LIQUID-CRYSTALS

An investigation is made of chaos in planar samples of nonchiral smect ic-C liquid crystals. When a static electric field is applied at an ob lique angle to the layers an explicit solitonlike solution is derived from the smectic continuum equations: this solution describes a moving domain wall. When a suitable oscillating electric field is superimpos ed on the static field this domain wall can be unstable and chaotic in stabilities are shown to arise in the movement of the c director. Crit eria for the onset of chaos are provided via a Melnikov analysis where , for example, for any given smectic tilt angle it can be decided whic h magnitudes and frequencies of the oscillating field lead to chaos.