Shaw Pankaj Kumar, Saha Debajyoti, Ghosh Sabuj, Janaki M S, Iyengar A N Sekar
Plasma Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064, India.
Chaos. 2015 Apr;25(4):043101. doi: 10.1063/1.4916772.
Experimental evidence of intrinsic noise induced coherence resonance in a glow discharge plasma is being reported. Initially the system is started at a discharge voltage (DV) where it exhibited fixed point dynamics, and then with the subsequent increase in the DV spikes were excited which were few in number and with further increase of DV the number of spikes as well as their regularity increased. The regularity in the interspike interval of the spikes is estimated using normalized variance. Coherence resonance was determined using normalized variance curve and also corroborated by Hurst exponent and power spectrum plots. We show that the regularity of the excitable spikes in the floating potential fluctuation increases with the increase in the DV, up to a particular value of DV. Using a Wiener filter, we separated the noise component which was observed to increase with DV and hence conjectured that noise can play an important role in the generation of the coherence resonance. From an anharmonic oscillator equation describing ion acoustic oscillations, we have been able to obtain a FitzHugh-Nagumo like model which has been used to understand the excitable dynamics of glow discharge plasma in the presence of noise. The numerical results agree quite well with the experimental results.
本文报道了辉光放电等离子体中本征噪声诱导相干共振的实验证据。最初，系统在一个呈现定点动力学的放电电压（DV）下启动，随后随着DV的增加，激发了数量较少的尖峰，并且随着DV的进一步增加，尖峰的数量及其规律性都增加了。使用归一化方差来估计尖峰的峰间间隔的规律性。通过归一化方差曲线确定相干共振，同时也通过赫斯特指数和功率谱图得到证实。我们表明，在浮动电位波动中，可激发尖峰的规律性随着DV的增加而增加，直至DV达到一个特定值。使用维纳滤波器，我们分离出了随DV增加的噪声成分，因此推测噪声在相干共振的产生中可能起重要作用。从描述离子声振荡的非简谐振荡器方程出发，我们得到了一个类似菲茨休 - 纳古莫模型，该模型用于理解存在噪声时辉光放电等离子体的可激发动力学。数值结果与实验结果相当吻合。
