Plasma discharges in bubbles remain an active area of research because of the associated applications in environmental remediation, agriculture and chemical processing. Plasmas in contact with the gas-liquid interface can drive chemical and physical processes, one of which is the mechanical surface perturbation leading to the formation of capillary waves. Using a 2-D discharge cell, capillary waves on the surface of a 2-D bubble are investigated. This study reports the observation of interfacial capillary waves on the gas-liquid interface excited by nanosecond pulsed plasma discharges. The capillary waves appear to be initiated by streamers coming into contact with the interface, with surface tension playing the role of the restoring force and viscosity contributing to damping. The waves propagating along the bubble's surface alter the bubble's shape. This capillary wave mode was found to be dependent on bubble size and plasma pulse frequency. Sympathetic resonant oscillations were also observed in adjacent bubbles, which indicate that capillary waves can drive acoustic oscillations and ultimately drive large-scale fluid effects. Additionally, strong surface perturbation was observed to modify the breakdown gap and as a result, led to self-organization of subsequent plasma streamers, which in turn sustains the capillary waves. In effect, plasma streamers and capillary waves are positively coupled to each other as a form of feedback, thus give insight into the interplay between plasma and fluid effects.

中文翻译：

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气液边界流注驱动机械扰动引起的界面振荡和自组织的实验观察

由于在环境修复、农业和化学加工中的相关应用，气泡中的等离子体放电仍然是一个活跃的研究领域。与气液界面接触的等离子体可以驱动化学和物理过程，其中之一是导致毛细波形成的机械表面扰动。使用二维放电单元，研究二维气泡表面的毛细波。这项研究报告了在由纳秒脉冲等离子体放电激发的气液界面上观察到的界面毛细波。毛细波似乎是由与界面接触的拖缆引发的，表面张力起恢复力的作用，粘性有助于阻尼。沿着气泡传播的波' s 表面会改变气泡的形状。发现这种毛细管波模式取决于气泡大小和等离子体脉冲频率。在相邻气泡中也观察到了交感共振，这表明毛细波可以驱动声学振荡并最终驱动大规模流体效应。此外，观察到强烈的表面扰动会改变击穿间隙，结果导致后续等离子体流注的自组织，从而维持毛细波。实际上，等离子流光和毛细波作为一种反馈形式相互正耦合，从而深入了解等离子和流体效应之间的相互作用。在相邻气泡中也观察到了交感共振，这表明毛细波可以驱动声学振荡并最终驱动大规模流体效应。此外，观察到强烈的表面扰动会改变击穿间隙，结果导致后续等离子体流注的自组织，从而维持毛细波。实际上，等离子流光和毛细波作为一种反馈形式相互正耦合，从而深入了解等离子和流体效应之间的相互作用。在相邻气泡中也观察到了交感共振，这表明毛细波可以驱动声学振荡并最终驱动大规模流体效应。此外，观察到强烈的表面扰动会改变击穿间隙，结果导致后续等离子体流注的自组织，从而维持毛细波。实际上，等离子流光和毛细波作为一种反馈形式相互正耦合，从而深入了解等离子和流体效应之间的相互作用。导致后续等离子流的自组织，从而维持毛细波。实际上，等离子流光和毛细波作为一种反馈形式相互正耦合，从而深入了解等离子和流体效应之间的相互作用。导致后续等离子流的自组织，从而维持毛细波。实际上，等离子流光和毛细波作为一种反馈形式相互正耦合，从而深入了解等离子和流体效应之间的相互作用。