Reduction waves in the two-variable Oregonator model for the BZ reaction

Numerical simulations of the two-variable Oregonator in a one-dimensional reaction–diffusion model are undertaken to show the formation of single reduction pulses. These are seen to exist over relatively narrow ranges of the (dimensionless) kinetic parameters ϵ and f arising in the derivation of the Oregonator model, though they are seen for all values of the diffusion coefficient ratio D considered. For the smaller values of D a direct transition from single reduction pulses to wave trains is found. For equal diffusion coefficients, D = 1.0 , this transition involves a sequence of complex spatio-temporal dynamics, including localized oscillatory behaviour and the successive spreading of a region in the reduced state. The present results are compared with results from the three-variable Oregonator and the Rovinsky–Zhabotinsky models for the BZ reaction, as well as with previous experimental observations.