Pattern formation during the oscillatory photoelectrodissolution of   n-type silicon: Turbulence, clusters and chimeras
  We report and classify the rich variety of patterns forming spontaneously in the oxide layer during the oscillatory photoelectrodissolution of n-type doped silicon electrodes under limited illumination. Remarkably, these patterns are often comprised of several dynamical states coexisting on the electrode, such as subharmonic phase clusters and spatio-temporal chaos, and include so-called 'chimera states'. The experiments suggest that the subharmonic phase clusters emerge from a period doubling bifurcation which, upon further parameter changes, evolve into classical phase clusters. Experimentally the occurrence of the patterns is controlled via two coupling mechanisms: A linear global coupling by an external resistor and a nonlinear coupling imposed on the system by the limitation of the illumination. 
Konrad Schoenleber and Carla Zensen and Andreas Heinrich and Katharina   Krischer
nlin.PS cond-mat.dis-nn nlin.CD