Heterogeneous Fluctuations in Chemical Oscillators

Abstract

Experimental evidence is given for large-scale concentration fluctuations (of the order of ± 2–100%) in the ferroin-catalyzed BZ reaction, observed in a stirred batch-reactor. Their essentially heterogeneous, spatially distributed nature is established by monitoring simultaneously the redox potential in a micro-volume and a macro-volume by using electrodes of different size. A typical record is shown in Fig.1. Fluctuations are absent from the largeelectrode record due to averaging over spatially distributed fluctuations. This represents a direct confirmation of the nucleation model and demonstrates a ubiquitous tendency of the system to differentiate spatially on a mesoscopic scale. We believe that fluctuations play a fundamental role in the global self-organization of unstirred systems.