Frozen spatial chaos induced by boundaries

We show that rather simple but nontrivial boundary conditions could induce the appearance of spatial chaos (that is stationary, stable, but spatially disordered configurations) in extended dynamical systems with very simple d ynamics. We exemplify the phenomenon with a nonlinear reaction-diffusion eq uation in a two-dimensional undulated domain. Concepts from the theory of d ynamical systems, and a transverse-single-mode approximation are used to de scribe the spatially chaotic structures. [S1063-651X(99)01812-7].