Self-organization induced by the differential flow of activator and inhibitor.

We have experimentally verified the prediction that a homogeneous steady state of an activatorinhibitor system can be destabilised by a differential flow of the ey species, rather than by their differential diffusivity as for the Turing instability. Traveling waves are generated by a flow of Belousov-Zhabotinsky reactants through a tube containing ferroin immobilised on a cation exchanger. Without flow the system resides in a homogeneous steady state. This mechanism of spatiotemporal pattern formation avoids the restrictions of the Turing irritability on the diffusion coefficients and can thus be expected to operate in a larger class of chemical, physical, and biological systems