Appearance and suppression of Turing patterns under a periodically forced feed

Turing instability is a general and straightforward mechanism of pattern formation in reaction-diffusion systems, and its relevance has been demonstrated in different biological phenomena. Still, there are many open questions, especially on the robustness of the Turing mechanism. Robust patterns must survive some variation in the environmental conditions. Experiments on pattern formation using chemical systems have shown many reaction-diffusion patterns and serve as relatively simple test tools to study general aspects of these phenomena. Here, we present a study of sinusoidal variation of the input feed concentrations on chemical Turing patterns. Our experimental, numerical and theoretical analysis demonstrates that patterns may appear even at significant amplitude variation of the input feed concentrations. Furthermore, using time-dependent feeding opens a way to control pattern formation. The patterns settled at constant feed may disappear, or new patterns may appear from a homogeneous steady state due to the periodic forcing.

Automated summary

Turing instability is a general mechanism of pattern formation in reaction-diffusion systems, which has been observed in various biological phenomena. However, the robustness of the Turing mechanism remains uncertain. This study investigates the effect of sinusoidal variation of input feed concentrations on chemical Turing patterns, and demonstrates that patterns can still emerge even with significant amplitude variation. Moreover, time-dependent feeding can be used to control pattern formation, leading to the disappearance of settled patterns or the emergence of new patterns from a homogeneous steady state.