中文摘要：

为研究大气压氩气等离子体羽的脉冲放电特性及其放电机理,以氩气为工作气体,在大气压空气环境中,利用直流激励的等离子体喷枪产生了圆锥形均匀的等离子体羽。等离子体羽长度随气流的增大而增大,但几乎不随两电极间维持电压的变化而变化。通过对两电极间维持电压、放电电流、放电发光信号的时间演化图分析,发现尽管维持电压是恒定的,放电电流和放电发光表现为周期性的脉冲。放电脉冲频率随维持电压的增大而增大,且随两电极间距离的增大而减小。对不同位置的发光信号时间演化进行研究,表明这种脉冲等离子体羽与常见的持续模式和子弹模式不同,其放电在不同的空间位置几乎是同时产生的,但是放电的熄灭却沿远离喷嘴的方向依次推迟。

英文摘要：

In order to investigate the pulse characteristics and the discharge mechanism of atmospheric pressure argon plasma plume, we used an atmospheric pressure plasma jet to generate cone-shaped uniform plasma plume in ambient air with argon used as working gas. It is found that the length of plume increases with increasing gas flow rate but barely changes with sustaining voltage. We also analyzed the plume discharge in the aspects of temporal evolution of current, light emission and sustaining voltage. It is obtained that the discharge occurs repetitively in pulsed mode in spite of the sustaining DC voltage. The pulse frequency increases with increasing sustaining voltage, but decreases with increasing gap width. According to the temporal evolution of light emission at different positions, plasma plume is different from ordinary jets in continuous mode or plasma bullet mode： the discharges almost initiate at the same moment, but they quenches in sequence in a direction away from the jet nozzle.