Chemical instability induced by an electric field

In a quasi-one-dimensional reaction-diffusion-migration system based on the methylene blue-sulfide-oxygen oscillatory reaction in a matrix of polyacry lamide gel, almost stationary patterns are observed. A weak electrical fiel d applied to the system induces waves which travel toward the cathode. Clos e to the anode, the initially observed stationary pattern remains stable. I n some experiments, a lateral instability of the wave front is also observe d. The spatio-temporal dynamics is analyzed by the Karhunen-Loeve decomposi tion technique, and entropy-like quantities are used to describe the dynami cs. Numerical simulations based on a chemically realistic model confirm the experimental observations.