Synchronization and clustering in globally coupled salt-water oscillators

Collective dynamics in globally coupled salt-water oscillators is studied as a function of coupling parameter and system size. The coupling parameter is controlled by changing the ratio of the surface area of the cup to that of the outer vessel. Antiphase and cluster states are observed as ordered states at a large coupling parameter. The appearances of such states are restricted to the case of a small number of constituent oscillators. For a large population of the oscillator, it is found that coupling among oscillators is promoted with the coupling strength, but there is some limitation in a degree of coupling induced. Furthermore, the effect of viscosity on coupling behaviors is investigated. These results are discussed using the idea of frustration developed in the area of the spin system.