OBSERVATION OF STOCHASTIC COHERENCE IN COUPLED MAP LATTICES

Chaotic evolution of structures in a coupled map lattice driven by ide ntical noise on each site is studied (a structure is a group of neighb oring lattice sites for which values of the dynamical variable follow a certain predefined pattern). The number of structures is seen to fol low a power-law decay with length of the structure for a given noise s trength. An interesting phenomenon, which we call stochastic coherence , is reported in which a rise of bell-shaped type in abundance and lif etimes of these structures is observed for a range of noise-strength v alues.