氩气等离子体羽从实心到空心的放电特性

对大气压环境中偏置正弦电压激励的氩气等离子体射流进行了研究. 结果表明,随着偏置电压从负值增加到正值,所产生的羽从实心过渡到空心. 利用电学和光学手段对实心羽和空心羽的放电特性进行了研究,发现对于这2种羽,每个电压周期都只有单个放电脉冲. 利用快速摄影,看到“胖”定向子弹在实心羽中传播,其中涉及负流光机制. 而空心羽中涉及正流光机制,它表现为从棒电极端开始的定向流光,随后逐渐演变成在气流周边传播的分叉流光. 利用光谱学手段,研究了距离管口不同位置处的电子温度. 基于潘宁电离和残留负离子的作用,对这2种羽的产生机制进行了解释.

Discharge characteristics of argon plasma plume from solid to hollow

The argon plasma jet excited by a biased sinusoidal voltage are investigated in an atmospheric pressure environment. The results show that as the biased voltage increases from negative to positive, the resultant plume transits from solid to hollow. The discharge characteristics of solid plume and hollow plume are studied by electrical and optical means, and it is found that there is only one discharge pulse per voltage cycle for these two plumes. Through fast photography, the plump guided bullet is found to propagate in the solid plume, which involves a negative streamer mechanism. The hollow plume involves a positive streamer mechanism, which manifests as a thin guided streamer starting from the end of the driven electrode, and then gradually evolving into branching streamers propagating in the flow periphery. By spectroscopy, the electron temperature of the different positions from the nozzle are studied. Based on the interaction of Penning ionization and residual negative ions, the production mechanism of these two plumes is explained.