Experimental study of the dimensionality of black-eye patterns

The spatial structure of one type of Turing pattern named “black eyes” is studied in experiments using the chlorite–iodide–malonic acid reaction in spatial open reactor. The purpose of the work is to verify (or falsify) two possible theoretical interpretations of black-eye pattern formation: the projection of a body-centered-cubic (bcc) structure onto the plane vertical to the body diagonal and the spatial resonance of larger wave vectors with the fundamental ones. The latter happens when the mode of the larger wave vectors becomes linearly unstable, as the system goes far beyond the onset of Turing bifurcation. Our experimental results give evidence that black-eye patterns are not a projection of the bcc structure, so that the interpretation of a three-dimensional structure can be ruled out. The observations in the experiment also suggest another possible mechanism for the formation of black eyes.