Experimental observation of interfacial oscillations and self-organization derived from streamer-driven mechanical perturbation of a gas–liquid boundary
Experimental observation of interfacial oscillations and self-organization derived from streamer-driven mechanical perturbation of a gas–liquid boundary
复制标题
流光驱动的气液边界机械扰动产生的界面振荡和自组织的实验观察
DOI：
10.1088/1361-6595/ab51bf
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发表时间：
2019
影响因子：
3.8
通讯作者：
J. Foster
中科院分区：
文献类型：
--
作者：
Janet Lai;J. Foster
气泡中的等离子体放电由于在环境修复、农业和化学加工中的相关应用，仍然是一个活跃的研究领域。与气 - 液界面接触的等离子体能够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。利用二维放电室，对二维气泡表面的毛细波进行了研究。本研究报告了对纳秒脉冲等离子体放电激发的气 - 液界面上的界面毛细波的观测结果。毛细波似乎是由流注与界面接触引发的，表面张力起到恢复力的作用，而粘性有助于阻尼。沿气泡表面传播的波会改变气泡的形状。发现这种毛细波模式取决于气泡大小和等离子体脉冲频率。在相邻气泡中还观察到了共振振荡，这表明毛细波能够驱动声振荡并最终驱动大规模的流体效应。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，这反过来又维持了毛细波。实际上，等离子体流注和毛细波作为一种反馈形式彼此正耦合，从而深入了解等离子体和流体效应之间的相互作用。
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 2D discharge cell, capillary waves on the surface of a 2D 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.