局域环境中微波等离子体电子密度诊断实验研究

为了研究局域真空环境中微波等离子体喷流电子数密度的分布规律及其影响因素，利用发射/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：在有约束边界条件下，微波等离子体发生器以60 W以下的微波功率击穿流量范围是21—105 mg/s的氩气时，所产生的喷流中电子数密度分布在8.8×10¹⁴—7.53×10¹⁶/m^{3关键词： 等离子体诊断技术 等离子体基本过程 等离子体基本特性}

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

In order to diagnose the electron density of microwave plasma jet confined by solid boundary walls, the emission/Langmuir probe was applied to measure the plasma space potential and current and voltage property when the probe is charged by heating and scanning power supply separately. According to the plasma space potential, saturated current on the current-voltage characteristics of plasma can be distinguished, which can be used to estimate the number density of electrons in the plasma. The results show that the magnitude of electron density ranges from 8.8×10¹⁴ to 7.53×10¹⁶/m³, the electron density on the centerline of jet decreases linearly off the nozzle exit plane, but it has approximately parabolic distribution along the plasma jet direction when leaving the centerline. Increasing mass flow rate at constant power and increasing power at constant mass flow rate will increase electron density.