The effect of background fluctuation on velocity diagnostics is discussed and studied. The kinetic theory of Mach probe (MP) and the theory of BGK mode are combined to evaluate how the measurement of MP is affected by electrostatics fluctuation. It is found that the quantity of speed by the MP model is closer to the effective velocity in the picture of momentum flux rather than the real mean velocity, while, with high fluctuation, the fitting parameter of MP’s exponential formula should be corrected.

中文翻译：

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背景波动对马赫探针速度诊断的影响

讨论和研究了背景波动对速度诊断的影响。结合马赫探针（MP）的动力学理论和BGK模式理论，评估静电波动对MP测量的影响。发现MP模型的速度量更接近动量通量图中的有效速度而不是实际平均速度，而波动较大时，需要对MP指数公式的拟合参数进行修正。