RESUMO
In a dc-driven planar gas discharge system with a semiconductor electrode, the homogeneous stationary discharge state can be destabilized in favor of current filaments. A filament consists of a succession of spatially confined breakthroughs of the gas layer that repeatedly take place at approximately the same position. A pulsating filament is thus slowly moving over the active area of the system. At fixed parameters, processes of creation and quenching of filaments are observed, while their average spatial density depends on control parameters. Depending on the density, filaments arrange in different configurations. At an intermediate value of filament density, a pattern on a two-dimensional domain is found: it is a spatially anisotropic chain pattern that is specified by two characteristic spatial scales. It is suggested that the observed phenomena are due to a Hopf-Turing instability arising in the system.
