Multiple Time Scale Expansion Research Articles

Chemical relaxation pulses and waves. Analysis of lowest order multiple time scale expansion

We analyze the propagation of pulses and wave trains in a chemical reaction–diffusion system far from equilibrium whose kinetics are characterized by multiple time scales. The previously derived equations describing this system in the limit of widely separated time scales are employed. For a two-component system we derive lowest order expressions relating the velocity of a propagating front to the chemical kinetics. These expressions are used to obtain the structure of solitary pulses. The mechanics of this pulse propagation is further investigated with simple integral transform methods in a multiple time scale system whose kinetics contain linear flux. Finally, we derive the structure of wave trains in these systems and the relation between their velocity and frequency in terms of the chemical kinetics.