混沌动力学方法在等离子体尾迹流场研究中的应用

用混沌动力学方法对多道扫描静电探针的离子饱和电流信号进行分析,研究了等离子体尾迹流场.通过对相关维、Renyi熵和最大Lyapunov指数的分析,得到了近尾流场的分层结构.利用最大Lyapunov指数,观测到了在x>10D以后的远尾流场与自由流场相似.结合探针信号的自相关函数,研究流场湍流结构,发现近尾可能存在大涡拟序结构,而在远尾则没有湍流.观察到了流场具有一定的间歇特征,认为这种间歇性与湍流有关.结果还表明,混沌动力学的分析方法对信号中非周期成分十分敏感,在研究等离子体尾迹流场这一类非线性系统时,它具有明显的优越性关键词：混沌动力学尾迹等离子体湍流静电探针

Application of chaos dynamics to the research on plasma wakes

A plasma wake flow field is studied by analyzing the saturated ionic current of multiple scanning probes with the method of chaos dynamics.The laminated structure of near wake is verified by analyzing the correlation dimension,the Renyi entropy and the largest Lyapunov exponent.It is observed that when x>10D , the far wake flow field is similar to the free flow field.By studying the autocorrelation function of the probe signal,it is found that the large eddy quasi ordering structure likely exists in near wake,but there is no turbulence in far wake.The intermittent character of the flow field can be discovered,and it seems to produce a certain relationship between the intermittent character and the turbulence.All the results show that the analytic method of chaos dynamics is sensitive to the non periodic signal,so it is useful in studying the plasma wake.