Microwave cavity resonance spectroscopy is introduced and demonstrated as a new approach to investigate the generation of acoustic waves by a pulsed radio-frequency driven atmospheric-pressure plasma jet. Thanks to recent advancements in the diagnostic method, the lower detection limit for pressure changes in air is ∼0.3 Pa. Good agreement with conventional pressure transducer measurements with respect to the temporal evolution, the pressure amplitude and the spectral response is found. Fourier analysis revealed that the acoustic waves induced by the plasma can most likely be attributed to standing waves in the discharge geometry. Additionally, the plasma-induced acoustic waves of a few (tens of) Pa are proposed as an active mechanism in plasma medicine.

中文翻译：

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共振微波探测来自射频等离子体射流的声波

微波腔共振光谱作为一种新的方法来研究由脉冲射频驱动的大气压等离子体射流产生的声波。由于诊断方法的最新进展，空气中压力变化的检测下限约为 0.3 Pa。发现在时间演变、压力幅度和光谱响应方面与传统压力传感器测量结果非常吻合。傅立叶分析表明，等离子体引起的声波最有可能归因于放电几何结构中的驻波。此外，提出了几（几十）Pa 的等离子体诱导声波作为等离子体医学中的一种活性机制。