Front interaction on a ring electrode

Abstract

Recent electrochemical experiments and simulations by Krischer and co-workers on a ring electrode reveal a unique transition mechanism for a bistable reduction reaction. The front boundaries of a localized pulse of higher potential are seen to accelerate around the ring to induce a very rapid transition. We show here that the accelerated transition is due to attractive front interaction across the pulse initially and around the ring in the final stage. Using coherent structure theory, we quantitatively correlate this interaction-induced acceleration to the dimensions of the electrodes. We also predict a critical width of the initial pulse below which the pulse will shrink and the transition is prevented.