双稳系统演化的时间尺度与随机共振的加强

噪声作用下的双稳系统存在着单一势阱内的随机波动和两势阱之间的概率跃迁，这两种不同层级的运动具有不同的时间尺度，且低层级的势阱内的波动影响着高层级的势阱间的跃迁．当外作用周期信号的时间尺度与噪声诱导的势阱间概率跃迁达到随机同步时，则能产生随机共振；给系统再加第二驱动周期信号，使其时间尺度与低层级的势阱内的波动相匹配，则存在着频率吸收现象，并能增强双稳系统的随机共振效应． 关键词： 随机共振 双稳系统 层级 时间尺度

Time scales of the evolution in bistable system and the reinforcement of stochastic resonance

Stochastic fluctuations in the single potential well and probability transitions between the two potential wells exist in the bistable system under the action of noise. These two kinds of movements in different hierarchies have different time scales, and the fluctuations in the low hierarchy potential well have effects on the transitions between high hierarchy potential wells. When time scale of the first input periodical signal and noise-induced probability transitions between the potential wells achieves stochastic synchronization, the phenomenon of stochastic resonance happens. When the second driven periodic signal, the time scales of which matches that of the intrawell fluctuations, is introduced into the system, the phenomenon of frequency absorption happens and the effect of stochastic resonance in bistable system is reinforced.