Transition to spatiotemporal chaos in the fronts dynamics of a subcritical state.

The evolution of the isolated domains of a bifurcated structure in a subcritical state is experimentally studied along the hysteresis branch, up to the critical point at which a chaotic regime is found to develop. The width of the domains is unstable and the fronts dynamics exhibit a cascade of bifurcations as the constraint increases. The chaotic regime is initiated by a splitting of the isolated domains, controlled by a width-selection mechanism. Most of these results are qualitatively reproduced in a fifth-order Ginzburg-Landau model.