等离子体推进器羽流电子密度微波干涉仪测量数据处理研究

发布时间：2018-04-11 16:46

本文选题：等离子体诊断 + 羽流　；参考：《中国科学院研究生院(空间科学与应用研究中心)》2015年硕士论文

【摘要】：微波干涉仪是等离子体电子密度探测的有效方法。利用微波干涉仪可以进行推进器羽流电子密度的探测。本文针对推进器羽流电子密度探测开展研究,首先对等离子体诊断的方法进行了分析,对比了几种常用的电子密度诊断方法。论文介绍了用于等离子体密度探测的微波干涉仪的测量原理和实现类型;结合测量原理与测量环境条件,讨论了微波干涉仪设计及与具体应用需求相关的频率选择、诊断干扰等问题。论文重点研究利用微波干涉仪进行推进器羽流密度测量的反演方法,针对羽流等离子体密度反演的Abel逆变换数值求解,对离散化法、三次样条插值法、Hankel-Fourier法以及Nestor-Olsen法等四种方法进行仿真分析和比较。分析了噪声、数据点数对结果的影响,并在此基础上提出数据预处理步骤及实现方法。论文讨论了两次干涉实验,验证了探测系统的设计指标和反演算法的有效性。两次实验均利用矢量网络分析仪搭建微波干涉系统,以扫频方式进行。实验一以管材为被测件进行测量,通过反演测量数据得到管材的空间位置信息。实验二为螺旋波等离子体推进器地面模拟实验,实验所用频率为30GHz-40GHz,实验中对羽流某截面进行径向扫描,利用实验数据反演得到该截面的电子密度径向分布曲线。根据诊断结果,被测羽流截面的电子密度在1017m-3量级,峰值达到1018m-3。实验结果表明,本文提供的算法用于羽流密度反演问题取得了很好的效果。论文给出的羽流模拟实验结果对后续的推进器研究和实验设计有很大参考价值。
[Abstract]:Microwave interferometer is an effective method to detect electron density of plasma.The electron density of propeller plume can be detected by microwave interferometer.In this paper, the plume electron density detection of propeller is studied. Firstly, the methods of plasma diagnosis are analyzed, and several commonly used electronic density diagnosis methods are compared.Diagnose problems such as interference.In this paper, the inversion method of plume density measurement using microwave interferometer is studied. The numerical solution of the inverse Abel transform of plume plasma density inversion is presented, and the discretization method is applied to measure the plume density.The cubic spline interpolation method is simulated and compared with Hankel-Fourier method and Nestor-Olsen method.The effects of noise and data points on the results are analyzed. Based on this, the data preprocessing steps and implementation methods are proposed.In this paper, two interference experiments are discussed, and the effectiveness of the design index and inversion algorithm of the detection system is verified.In both experiments, the microwave interference system was constructed by vector network analyzer.In the first experiment, the pipe is used as the measured part, and the spatial position information of the pipe is obtained by inversion of the measured data.The second experiment is the ground simulation experiment of helical wave plasma thruster. The frequency of the experiment is 30GHz ~ 40GHz. The radial scanning of a section of plume is carried out in the experiment, and the radial distribution curve of electron density of the section is obtained by using the experimental data.According to the diagnostic results, the electron density of the measured plume cross section is in the order of 1017m-3, with a peak value of 1018m-3.Experimental results show that the proposed algorithm is effective in plume density inversion.The results of the plume simulation experiment are of great reference value for the subsequent research and experimental design of propeller.
【学位授予单位】：中国科学院研究生院(空间科学与应用研究中心)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH744.3

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