Oscillatory cluster patterns in a homogeneous chemical system with global feedback. While clusters have received considerable attention in arrays of coupled neurons, they are rare in chemical systems. Such clusters resemble standing waves, except that clusters lack a characteristic wavelength. Standing clusters have fixed spatial domains and oscillate periodically in time.
Irregular clusters show no periodicity either in space or in time.
Localized clusters display periodic antiphase oscillations in one part of the medium, while the remainder appears uniform. Numerical simulations based on a model of the BZ reaction supplemented with global feedback showgood agreement with our experimental data. The results may have significance for neural as well as chemical and physical systems with global feedback.