Self-organized criticality and 1/f fluctuation under conditions of nonequilibrium phase transitions

The results are given of an experimental investigation of fluctuation pheno mena under conditions of electric arc discharge. Fluctuations are observed whose spectral density is inversely proportional to frequency (1/f noise). Power dependences are revealed of the fluctuation distribution functions. T he behavior of spectral density and of distribution functions is associated with the simultaneous occurrence of various nonequilibrium phase transitio ns. Within the framework of the mean field theory, a mathematical model is suggested of interacting nonequilibrium phase transitions in a distributed system, which predicts the self-organization of the critical state and the generation of fluctuations with diverging spectral characteristics. An adeq uate agreement is observed between the suggested model and experimental dat a. (C) 2001 MAIK "Nauka/Interperiodica".