Noise-reversed stability of Turing patterns versus Hopf oscillations near codimension-two conditions.

Pattern formation induced by noise is a celebrated phenomenon in diverse reaction-diffusion systems. Here we report numerical simulations with the Lengyel-Epstein model for the chlorine dioxide-iodine-malonic acid reaction when perturbed with an external spatiotemporal stochastic forcing in the vicinity of the Hopf and Turing codimension-two bifurcation. Competition between Turing and Hopf modes gives rise to the generation of transient Turing patterns evolving to stationary global oscillations. This situation is reversed by the introduction of external fluctuations and Turing patterns become dominant in this case. The increase in the spatial coherence is found for intermediate noise intensity and small correlation length.