Formation of Clusters of Localized States in a Gas Discharge System via a Self-Completion Scenario

Formation of extended structures composed of localized states via the self-completion scenario is observed. The localized states are actually current filaments in a dc driven planar semiconductor--gas discharge system. The structure grows from a solitary localized state in the subcritical domain, where the homogeneous state is stable. It is proved that compact hexagonal clusters form due to the attractive interaction between distant filaments. A semiphenomenological model of the activator-inhibitor type is proposed which suggests that the Turing mechanism triggers the phenomenon.