Single spiral wave induced by noise

Reaction systems far from thermodynamic equilibrium can form a fascinating wealth of spatio-temporal pattern. Noise is usually thought to spoil order. In our numerical simulation, the reaction diffusion system disturbed by environmental noise can constitute a stable well-ordered spatio-temporal pattern, chemical single spiral waves in two dimensions spatial domain. It is counterintuitive that noise plays a constructive role in the production and propagation of single spiral waves in this letter. When noise intensity exceeds a threshold, it will destroy the well-ordered spatio-temporal pattern and make system uniform. Too weak or too strong noise will make against the formation and propagation of spiral waves. In a certain noise level, spiral wave can be maintained in a medium, where such spiral cannot be observed in the absence of the noise.