高通鸟笼线圈激发螺旋波等离子体特性研究

研制了高通鸟笼线圈，使用氩气作为工质气体对射频天线的工作性能进行了初步评估。利用COMSOL5.4模拟出了鸟笼天线在13.56MHz的工作频率下，电场和磁场呈线性极化分布。对鸟笼线圈进行了电路结构解剖，推导出了其谐振频率计算公式。利用热耦合红外测温仪测试了正常工作状态下的鸟笼线圈外表温度明显低于传统射频天线，电容器最高温度仅65.8°。使用光谱仪对螺旋波等离子体放电光谱特性进行诊断。通过朗缪尔探针诊断了不同压强和磁场强度下螺旋波等离子体密度，在1.0Pa、600Gs、射频功率700W条件下等离子体密度达到1.62×10¹⁸m^-3。诊断了正向功率和反向功率对应的等离子体密度，其与磁滞现象变化趋势雷同。测试了螺旋波等离子体的径向密度分布，其在轴心处密度达到最高。探究了无磁场条件下等离子体特性，其密度值不会发生大幅度跃迁，纵向磁场是引发螺旋波等离子体放电的关键因素，低压条件下有利于得到更低的电子温度，最低达到2.67eV。表明鸟笼线圈低热耗、高馈入的特性使其在激发大体积的高密度螺旋波等离子体方面具有明显优势，可以投入到下一阶段氢气螺旋波等离子体的激...

Study on the characteristics of helicon plasma excited by high pass birdcage coil

A high-pass birdcage coil is developed as plasma source, and argon gas is used as working gas to preliminarily evaluate the performance of RF antenna. COMSOL5.4 is used to simulate the linear polarization distribution of the electric and magnetic fields of the cage antenna at 13.56MHz. The circuit structure of birdcage coil is dissected and the formula for calculating its resonant frequency is deduced. The outer temperature of the cage coil is significantly lower than that of the traditional RF antenna under normal working conditions, and the maximum temperature of the capacitor is only 65.8°. The spectral characteristics of helicon wave plasma discharge were diagnosed by spectrograph. The density of helicon wave plasma was diagnosed by Langmuir probe under different pressure and magnetic field intensity. The plasma density reached 1.62×10¹⁸m⁻³ at 1.0Pa, 600Gs and 700W RF power. The plasma density corresponding to forward and reverse power is diagnosed and the variation trend is similar to that of hysteresis. The radial density distribution of helicon wave plasma is measured, and its density reaches the highest at the axis. The characteristics of plasma in the absence of magnetic field were also investigated. The density value of plasma did not have a large transition. The longitudinal magnetic field was the key factor to trigger the helicon wave plasma discharge. The results show that birdcage coil has obvious advantages in the excitation of large volume and higher density helicon wave plasma due to its low heat consumption and high feed, which can be used in the next stage of hydrogen helicon wave plasma excitation.