Nucleation of solution convection channels as the first step in electro-hydrodynamic pattern formation

The evolution of luminescent electrohydrodynamic (EHD) convection patterns is observed in thin layer electrochemical cells. The applied cell voltage i s found to initiate a nucleation-type process in which autonomous convectio n channels form between the electrodes. With progressing time, more channel s of the same type along with irregularly shaped arrangements of such chann els are detected. Within a period of seconds, the system undergoes a transi tion from the disordered into an ordered state. Thereby, the well-known cel lular EHD convection structures emerge. However it appears that even in the stationary patterns the individual convection channels remain intact, cons tituting well discernible flow structures.