The development of spatial structure in an ionic chemical system induced by applied electric fields

The spatio-temporal structures that can arise in an ionic chemical system with a cubic autocatalytic reaction step (Gray-Scott kinetics) in the presence of an applied electric field are described. A linear stability analysis of the resulting reaction-diffusion-advection system, with different diffusion coefficients and consequently different electrochemical migration rates for the reacting species, suggests the possibility of both convective structures ('DIFICI') and Turing patterns (as well as interaction between them). The detailed linear analysis determines the domain of existence of these features in parameter space, the predictions from which are confirmed by extensive numerical simulations. These reveal that a wide variety of propagating structures can be sustained by the system, depending on the electric field strength and whether the ratio of diffusion coefficients of autocatalyst and substrate is above or below the critical values for Turing bifurcations.