Boundary effects in extended dynamical systems

In the framework of spatially extended dynamical systems, we present three examples in which the presence of walls leads to dynamic behavior qualitati vely different from the one obtained in an infinite domain or under periodi c boundary conditions. For a nonlinear reaction-diffusion model we obtain b oundary-induced spatially chaotic configurations. Nontrivial average patter ns arising from boundaries are shown to appear in spatiotemporally chaotic states of the Kuramoto-Sivashinsky model. Finally, walls organize novel sta tes in simulations of the complex Ginzburg-Landau equation. (C) 2000 Elsevi er Science B.V. All rights reserved.