Elsevier, Physica D: Nonlinear Phenomena, 1-2(115), p. 19-28
DOI: 10.1016/s0167-2789(97)00223-6
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For over 25 years it is known that the roll structure of electroconvection (EC) in the dielectric regime in planarly aligned nematic liquid crystals has, after a transition to defect chaos, the tendency to form chevron structures. We show, with the help of a coarse-grained model, that this effect can generally be expected for systems with spontaneously broken isotropy, that is lifted by a small external perturbation. The linearized model as well as a nonlinear extension are compared to simulations of a system of coupled amplitude equations which generate chevrons out of defect chaos. The mechanism of chevron formation is similar to the development of Turing patterns in reaction diffusion systems. ; Comment: 17 pages, Latex, 11 PS-figures, submitted to Physica D