等离子体湍流扰动诊断数据的系综平均与湍流物理概念的一致性问题

On consistency of the ensemble averages of plasma turbulent fluctuation diagnostic data with the turbulent concepts

讨论了等离子体湍流诊断数据分析中的统计系综平均问题。指出时间平均和样本平均作为近似系综平均可能存在的问题。对前者,建议用扰动量的统计系综平均值与它的均方根值的比值,来判断扰动量的随机性程度;对后者,说明该近似的精度在很大程度上取绝于样本数据时间总长度与扰动关联时间之间的数量级关系。本文还列举一些与等离子体湍流物理概念不一致的实验数据分析方法,以引起重视和讨论。

The basic questions in the ensemble averages of plasma micro-turbulence data are discussed. It is proposed that the ratio of the fluctuation average to its rms value be implemented to inspect its random degree if the time-average is adopted as the ensemble average. The precision of the approximation, characterizing the ensemble-average with samples-average, is determined by the relative magnitude of the total data-time length and the fluctuation correlation time. It appears that the data analysis is not always consistent with fundamental plasma turbulence concepts in some cases, and therefore the related discussion and comments are made.