AUTOWAVE PROPAGATION IN HETEROGENEOUS ACTIVE MEDIA

New results obtained in self-completion of autowaves using a two-layer gelled Belousov-Zhabotinsky (BZ) medium with immobilized catalyst fed from above are presented. The stability of the collision level of the primary and of the secondary waves as well as different final outcomes of their interaction are discussed. Colliding spiral waves lead to characteristic cusp-shaped structures of the secondary waves with a high positive curvature at the edge of the cusp. Propagating through the gel the corresponding wave fronts can break at the edge of the cusp. These breaks generate small self-reproducing double spirals which possess a higher frequency than a single spiral wave. The spatiotemporal evolution of the small double spiral depends on the size of the break and on the excitability of of the medium.