低气压氩气空心阴极放电自脉冲特性

Self-pulsing Characteristic of Hollow Cathode Discharge at Low Pressure Range in Argon

为了进一步提高空心阴极放电的稳定性,揭示空心阴极放电自脉冲现象的形成机理,利用柱型空心阴极放电装置,在低气压氩气环境下研究了空心阴极放电的自脉冲现象。测量得到了放电的伏安特性曲线、放电发光图像、自脉冲电流和电压的时间演化特性,以及气压、电流、外部限流电阻等对自脉冲的影响。研究结果表明,自脉冲放电出现在空心阴极放电的负阻特性阶段,并具有稳定的频率(几kHz到几十kHz);自脉冲的形成时间<10μs,而衰减时间为几十μs,其频率随平均电流的增加而线性增大。此外,外部串联限流电阻对自脉冲产生范围有重要影响,随着外加电阻值的升高,能够产生自脉冲的上限平均电流升高,下限平均电流降低,但是不会对自脉冲产生机理产生影响。

In order to increase the discharge stability and explore the mechanism of self-pulsing in hollow cathode discharge, the self-pulsing phenomenon was investigated in a cylindrical hollow cathode at low pressure in argon. The volt-ampere characteristics, the discharge images, and the time evolution of the current and voltage of self- pulsing were measured under different conditions. The influences of the gas pressure, the discharge current, and the external resistance on the self-pulsing were also studied. Results show that the self-pulsing can be observed in the negative differential resistance region of hollow cathode discharge. The pulse frequency ranges from several kilohertz to tens of kilohertz, and increases with the average current. It is determined mainly by the decay time of the current pulse. The external resistor in series has some influences on the discharge range where the self-pulsing exists. The self-pulsing can be created in a wider average current range as the resistance increasing.