DISORDERED WAVES IN AN EXCITABLE MEDIUM CONSISTING OF 2 LAYERS - CATALYTIC GEL AND NONCATALYTIC SOLUTION

Disordered waves in the light-sensitive Belousov-Zhabotinsky reaction (''ripples,'' i.e., aperiodic wave front deformations, labyrinthine pa tterns, and ''frazzle gases,'' i.e., erratically moving wave fragments ) were observed experimentally a few years ago, bur have so far not be en explained and modeled. The system, consisting of a gel with immobil ized catalyst covered by a catalyst-free solution, is motionless and h orizontally homogeneous. The observed disorder is related to enhanceme nt or breakups of fluctuation valleys. In the model presented here, th is destabilization is caused by inhibitor produced in the refractory t ail that diffusively surpasses the wave front via the upper solution l ayer. This is in agreement with experiments both qualitatively, i.e., in the overall appearance of the patterns, as well as quantitatively, regarding the eikonal relationship and autocorrelation analysis.