采用单针电极放电装置在氩气中产生了稳定的均匀等离子体。利用光学方法对单针放电特性进行了研究，结果表明单针放电等离子体的长度随外加电压峰值、气压的增大而增大，随空气含量的增大而减小。利用光电倍增管对单针电极放电等离子体羽的发光信号进行了空间分辨测量，发现靠近单针电极的羽头和等离子体羽其余部分放电行为不同。其中羽头源于针尖附近的电晕放电，它仅在外加电压负半周期的发光较强，正半周期发光几乎探测不到。而等离子体羽其余部分的放电在外加电压正、负半周期均存在，且正半周期强于负半周期。研究表明，外加电压正半周期的等离子体羽是源于发光光层（等离子体子弹）的传播，而负半周期等离子体羽的不同位置几乎同时放电。

A stable plasma is generated in argon by using a single needle discharge device. The characteristics of the discharge are investigated by optical methods. Results show that the plasma plume length increases with increasing the peak value of the applied voltage or gas pressure, decreases with increasing the air content. Spatially resolved measurement of light emission is conducted on the plasma plume with photomultiplier tubes. It has been found that the discharge near the needle point has a different behavior with other part of the plasma plume. The discharge in the plasma head originates from a corona discharge which emits light strongly at the negative half cycle, its emission is too weak to be detected in the positive half cycle. The other part of the plasma plume originates from the propagation of luminous cluster (plasma bullet) in the positive half cycle, and every position of which is almost volley in the negative half cycle.