Low temperature plasmas generated inside gas bubbles immersed in water is an effective method of rapidly transferring plasma generated reactive species to the water for applications in biomedicine, agriculture and environment. Reactive species are generally produced in the gas phase plasma and then solvate into the liquid. The large surface-to-volume ratio (SVR) of the bubble accelerates this process. In generating bubbles in water, aerosols and droplets are also contained within the bubble. These droplets also have a large SVR and so can be rapidly plasma activated. However, the presence of the droplets can also impact the propagation of the plasma in the bubble. In this paper, results are discussed from computational and experimental investigations of the formation and evolution of discharges in an air bubble immersed in water with an embedded water droplet. The computations were performed with a two-dimensional plasma hydrodynamics model. Experiments were performed with a quasi-2D bubble apparatus. In bubbles having a droplet, a plasma filament typically bridges from the powered electrode to the droplet, and then from the droplet to the bubble surface. A surface-hugging streamer also occurs on the inner bubble surface and on the surface of the droplet. Both surface streamers result in part from surface charge accumulation and can dominate the formation of reactive species that transport into the droplet. Increasing droplet conductivity suppresses propagation of the surface discharge and leads to a lower density of aqueous reactive species. Increasing conductivity of the surrounding water does not change the overall structure of the discharge but does slightly elevate the discharge intensity. The size and shape of the embedded droplet can significantly affect the formation and propagation of the streamer.

在浸入水中的气泡内部产生的低温等离子体是一种将等离子体产生的反应性物种快速转移到水中的有效方法，可用于生物医学，农业和环境。通常在气相等离子体中产生反应性物质，然后将其溶剂化成液体。较大的气泡表面积与体积比（SVR）加快了此过程。在水中产生气泡时，气泡内还包含气溶胶和液滴。这些液滴还具有较大的SVR，因此可以快速进行等离子体活化。但是，液滴的存在也会影响气泡中等离子体的传播。在本文中，通过计算和实验研究讨论了结果，该研究是对浸没在水中并带有嵌入式水滴的气泡中放电的形成和演化进行的。使用二维等离子体流体动力学模型进行计算。实验用准二维气泡仪进行。在具有液滴的气泡中，等离子体灯丝通常从通电电极到液滴，然后从液滴到气泡表面桥接。在气泡的内表面和液滴的表面上也都出现了一个表面拥抱流光。两种表面流光都是部分由表面电荷积累引起的，并且可以主导传输到液滴中的反应性物质的形成。液滴电导率的增加抑制了表面放电的传播，并导致水性反应物的密度降低。周围水的电导率增加不会改变排放的总体结构，但会稍微提高排放强度。嵌入的液滴的大小和形状会显着影响拖缆的形成和传播。