Noise-enhanced phase locking in a chemical oscillator system.

Dynamical responses of a chemical oscillator to an external electric field were investigated in the Belousov-Zabotinsky reaction system with the catalyst Ru(bpy)(3)(2+) [tris-(2,2(')-bipyridine) ruthenium (II)] immobilized in cation exchange beads. Periodic forcing above the threshold induced phase locking, whose synchronization region has a shape similar to the Arnold tongue. When a certain amount of noise together with a subthreshold periodic signal was imposed on the chemical oscillator, 1:1 phase locking to the periodic signal occurred. Its degree passed through a maximum with increase in the noise intensity, a manifestation of stochastic resonance in the form of noise-enhanced phase locking. The experimentally observed features were reproduced in a numerical simulation with a forced Oregonator reaction-diffusion model.