Time-resolved characterization of a free plasma jet formed off the surface of a piezoelectric crystal
Time-resolved characterization of a free plasma jet formed off the surface of a piezoelectric crystal
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DOI：
10.1088/1361-6595/ab7987
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发表时间：
2020-04
影响因子：
3.8
通讯作者：
Jinyu Yang;S. Im;D. Go
中科院分区：
文献类型：
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作者：
Jinyu Yang;S. Im;D. Go
当压电Transformer（PT）由低输入电压（100 V）致动时，机电耦合导致在远端处的非常高（103 V）的表面电势，这可以使周围气体膨胀并导致从表面发出的等离子体射流。PT由于其操作简单、所需输入电压低和功耗低而对于非平衡等离子体产生具有吸引力。在这项工作中，时间分辨特性的自由表面等离子体射流所产生的PT在开放的空气中进行了研究。通过增强型CCD摄像机对PT驱动等离子体的时间演化进行了可视化，并将等离子体形成与等离子体射流的电流行为相关联。值得注意的是，等离子体形成是一个离散的过程，出现在正弦输入的相对固定的相位，最强的等离子体射流出现在正半周期的结束。电流的同步测量表明，放电电流响应与等离子体射流的混沌模式一致，并且在统计上比等离子体射流发光早1 μs，这表明存在较强的余辉。由于操作所需的低输入电压，这些类型的PT驱动等离子体射流在实验室之外的新兴等离子体应用中具有广泛的实用性，例如在医疗保健和水处理中。
When a piezoelectric transformer (PT) is actuated by a low input voltage (∼10 V), electromechanical coupling leads to a very high (∼103 V) surface potential at the distal end that can ionize the surrounding gas and lead to a plasma jet emanating from the surface. PTs are attractive for non-equilibrium plasma generation because of their simple operation, low required input voltage, and low power consumption. In this work, the time-resolved characteristics of the free surface plasma jet generated by a PT operating in open air have been investigated. The temporal evolution of the PT-driven plasma was visualized by using an intensified CCD camera and plasma formation was correlated with the current behavior of the plasma jet. Notably, the plasma formation is a discrete process, appearing at a relatively fixed phase of the sinusoidal input, and the strongest plasma jet appears at the end of the positive half-cycle. Simultaneous measurements of the current show that the discharge current response is consistent with the chaotic mode for a plasma jet and appears statistically about a 1 μs earlier than plasma jet light emission, which indicates that there is a strong afterglow. With a low input voltage required for operation, these types of PT-driven plasma jets could have wide utility in emerging plasma applications beyond the laboratory, such as in healthcare and water treatment.