Localized particle-like excitations in a gas discharge system and their dynamics

点击翻译按钮获取中文摘要

Systems driven out of equilibrium often show spontaneous organization of macroscopic structures from an initial featureless state ; these structures are found in diverse physical, chemical and biological systems in nature, and they are either globally distributed throughout the system or highly localized and particle like. Because such macroscopic structures are, in general, maintained by the balance between continuous supply of energy and/or materials to the system and its dissipation, Prigogine named them as 'dissipative structures' to distinguish it from microscopic 'equilibrium structures' such as crystals. Although dissipative structures share some features with equilibrium structures, the former is quite different from the latter in the point that the former is capable of showing a variety of dynamic behaviors that are never observed in the latter. Indeed, many nonequilibrium systems are known to exhibit complex evolution of globally distributed dissipative structures in one and … More two spatial dimensions and their dynamics has been extensively studied. Complex dynamics of one-dimensional localized dissipative structures has also been observed in many systems. But few examples are known for two-dimensional localized dissipative structures, and little is known about their behaviors.We find that highly localized, dynamic particle-like excitations are self-organized in a d.c.-driven, quasi two-dimensional gas-discharge system. These localized excitations (spots) exhibits quite irregular motion even when a single spot is present, and form either isolated or aggregated state when more than one spot is present, depending on the control parameter values. In aggregated state, they form a wandering molecule-like cluster, whose internal structure changes intermittently by rearranging mutual position of elements. The fact that these localized excitations can show synchronous dynamics even in distant places, together with recent theoretical studies, indicates that a global coupling plays an important role on the dynamics of such localized excitations. Less