CHARACTERIZATION OF WAVE FRONT INSTABILITIES IN THE BELOUSOV-ZHABOTINSKY REACTION: AN OVERVIEW

Abstract

Two types of instability of wave front propagation are compared. Reaction-induced or lateral instability leads to wave front fragmentation in systems having low excitability and high threshold of excitation. On the contrary, diffusion-induced instability was shown theoretically to cause wave front folding in systems with different diffusion of the autocatalyst and the inhibitor. First experiments pointing in this direction are presented. From wavelength λ 0 , velocity c0 of spiral waves and diffusion coefficient D of the autocatalytic species the dimensionless quantity Q=λ 0 c 0 /D is calculated for experimental characterization of lateral instability in different chemical systems. Furtheron, the connection between front curvature and fragmentation is analyzed. Various experimental possibilities to realize unstable wave propagation are summarized.