Non-equilibrium plasma in liquid water: dynamics of generation and quenching
Non-equilibrium plasma in liquid water: dynamics of generation and quenching
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DOI：
10.1088/0963-0252/20/2/024003
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发表时间：
2010-06
影响因子：
3.8
通讯作者：
A. Starikovskiy;Yong Yang;Young I Cho;A. Fridman
中科院分区：
文献类型：
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作者：
A. Starikovskiy;Yong Yang;Young I Cho;A. Fridman
在大多数情况下，液体的电击穿是通过在电极上施加高电场而引发的，随后是等离子体通道的快速传播和分支。典型地，等离子体仅被认为通过气体的电离而存在，并且在液体中等离子体的典型产生通过加热或经由空化而产生气泡，并且将等离子体维持在这些气泡内。问题出现了：有没有可能在不开裂和不形成空隙的情况下将液体溶解？为了回答这个问题，我们使用了脉冲功率系统，脉冲幅度为32-220 kV，脉冲持续时间为0.5-12 ns，上升时间为150 ps。放电单元具有尖端直径为100 µm的点对板几何形状。这些参数使我们能够观察到非平衡等离子体的产生。在4Picos ICCD相机的帮助下进行测量。结果表明，液态水中的放电形成于皮秒量级的时间尺度上。发射强度的增加和等离子体的形成需要200-300 ps。高压电极尖端附近的激发区域的直径为10.1 mm。在该初始阶段之后，发射迅速减少，并且等离子体区域在500 ps之后变得几乎不可见。在脉冲的其余部分期间没有发射可以通过导电区的边界上的电场的减小来解释。因此，我们已经证明了在液相中形成非平衡等离子体的可能性，并研究了在液态水中的非平衡等离子体的激发和猝灭的动力学。
In most cases, the electric breakdown of liquids is initiated by the application of high electric field on the electrode, followed by rapid propagation and branching of plasma channels. Typically plasmas are only considered to exist through the ionization of gases and typical production of plasmas in liquids generates bubbles through heating or via cavitation and sustains the plasmas within those bubbles. The question arises: is it possible to ionize the liquid without cracking and void formation? To answer this question we used a pulsed power system with 32–220 kV pulse amplitude, 0.5–12 ns pulse duration, 150 ps rise time. The discharge cell had a point-to-plate geometry with a tip diameter of 100 µm. These parameters allowed us to observe non-equilibrium plasma generation. The measurements were performed with the help of a 4Picos ICCD camera. It was found that the discharge in liquid water forms on a picosecond time scale. The increase of emission intensity and plasma formation took 200–300 ps. The diameter of the excited region near the tip of the high-voltage electrode was ∼1 mm. After this initial stage emission rapidly decreased and the plasma region became almost invisible after 500 ps. The absence of emission during the rest of the pulse is explained by a decrease of the electrical field on the boundary of the conductive zone. Thus we have demonstrated the possibility of formation of non-equilibrium plasma in the liquid phase and investigated the dynamics of excitation and quenching of non-equilibrium plasma in liquid water.