微波探针在磁化等离子体中参数诊断的实验研究

The diagnostic of magnetized plasma parameters is an important part of plasma industry development. Compare to traditional Langmuir probe, Microwave probe have more unique advances in diagnosis of industrialization plasma. The research of microwave probe to explore measurement principle of magnetized plasma is the premise for us to concise the usable and reliable method of diagnosing the plasma density and distribution. This project simulates the propagation characteristic of surface wave along microwave probe in the magnetized plasma, and discusses different influences on measuring results generated by parametric variations. What's more, it aims to explore relevant numerical modeling and guide the parameter diagnosis experiments of magnetized plasma under diverse discharge parameter. We will examine the final diagnosis results by Langmuir probe and various microwave probes. In the previous study, there is large number focused on parameter diagnosis of non-magnetic plasma by microwave probe. However, in the research field of magnetized plasma, the theory of microwave probe is still inadequate. It requires a further inter-exploration between theory simulation and experiment, as well as a carefully study the interaction between microwave probe and magnetized plasma. This is the significant purpose of promoting this project. The successful enforcement of this project will complete the relevant theory of microwave probe and gain a dependable diagnosis method which is capable for spatial discrimination of magnetized plasma density.

磁化等离子体参数的诊断是当前等离子体应用的重要环节。微波探针在应用等离子体诊断时与传统的静电探针相比具有很多独特的优势。微波探针对磁化等离子体的测量原理的研究，是凝炼使用可靠的等离子体密度以及其分布的诊断方法的前提。本项目在磁化等离子体环境中模拟微波探针上多种模式表面波及体积波的传播特性，探讨各参数变化对测量结果的影响，发展相关的数值模拟技术，指导各种放电参数下磁化等离子体参数诊断的实验，并以静电探针相互校验。微波探针对非磁化等离子体的参数诊断已有大量的研究。但在磁化等离子体中，微波探针理论仍然不足，需要理论模拟和实验结果相互论证，细致研究微波探针与磁化等离子体的相互作用。这些也是本项目的重要目标。本项目的成功实现，将完善微波探针的相关理论，获得磁化等离子体密度的具备空间分辨的适用可靠地诊断方法。

本项目通过研究等离子体表面波在不同参数下等离子体中的传播规律，开展了微波探针对磁化等离子体密度测量原理的研究，原创地提出了背向微波吸收探针等诊断方法，给出了等离子体密度诊断优化方案，为等离子体物理实验研究提供了多种有效的密度诊断方法。.利用电磁场仿真对敏感型吸收探针和微波截止探针两种微波探针的特性进行了研究，指出了以往敏感型吸收探针理论的不足，完善了敏感型吸收探针相关理论，表明了微波截止探针在磁化低温等离子体诊断方面同样适用。结合等离子体表面波、体积波传输的具体参数，设计了连续扫频单边带调制微波测量电路，研究了微波探针在磁化等离子体中的谐振特性，给出了谐振频率随电子回旋频率的变化规律，通过分析中频信号特征，获得微波探针的谐振频率，进而完成等离子体密度的测量。原创地提出了一种等离子体密度诊断方法：背向微波探针诊断。通过微波在强碰撞等离子体中传输时幅度的衰减，利用色散关系提供等离子体密度分布。背向微波探针具有位型良好、结构简单合理，抗干扰性强信噪比高的优点。