真空中微波等离子体喷流电子数密度分布规律实验研究

Diagnostic study on the electron density distribution of microwave plasma jet in vacuum environment

为了准确诊断真空中微波等离子体喷流的电子数密度,利用统一的发射和单郎缪尔探针测量等离子体的空间电位,再测量等离子体的电流-电压特性曲线.根据空间电位测量结果,在等离子体的电流-电压特性曲线上能准确地获取饱和电流,从而处理出电子数密度.最后的诊断实验表明,当真空环境压强为2—6Pa、等离子体发生器以60W以下的微波功率击穿流量范围是42—106mg/s的氩气时,所产生的微波等离子体喷流中电子数密度分布在1×1016—7·2×1016/m3范围内.

In order to diagnose precisely the electron number probe whose function is the same as that of emissive and density of microwave plasma jet in vacuum environment, the integrative Langmiur ones was applied to measure the plasma space potential and its current and voltage property when the probe is charged by the electric power of emissive probe and scanning electric power separately. According to the plasma space potential, saturated current on the current-voltage curve of plasma can be determined, which can be used to estimate the number density of electrons. The experimental results show that the number density of electrons in microwave argon plasma jet in vacuum environment is 1 × 10^16-7.2 × 10^16/m^3 , when the vacuum pressure is 3.2 and 5.4 Pa, the microwave output power is under 60 W and gas mass flow rate is in the range of 42-106 mg/s.