螺旋波等离子体原型实验装置中天线的优化设计与功率沉积  

Optimal design of helicon wave antenna and numerical investigation into power deposition on helicon physics prototype experiment

作　　者：平兰兰 张新军 杨桦 徐国盛 苌磊 吴东升 吕虹 郑长勇 彭金花 金海红 何超 甘桂华 Ping Lan-Lan;Zhang Xin-Jun;Yang Hua;Xu Guo-Sheng;Chang Lei;Wu Dong-Sheng;Lü Hong;Zheng Chang-Yong;Peng Jin-Hua;Jin Hai-Hong;He Chao;Gan Gui-Hua(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China;University of Science and Technology of China, Hefei 230026, China;School of Electronics and Information Engineering, Anhui Jianzhu University, Hefei 230601, China;School of Aeronautics and Astronautics, Sichuan University, Chengdu 610065, China;School of Electronic Engineering, National University of Defense Technology, Hefei 230036, China)

机构地区：[1]中国科学院等离子体物理研究所,合肥230031 [2]中国科学技术大学,合肥230026 [3]安徽建筑大学电子与信息工程学院,合肥230601 [4]四川大学空天科学与工程学院,成都610065 [5]国防科技大学电子对抗学院,合肥230036

出　　处：《物理学报》2019年第20期223-233,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61471002,61372094,11405271);安徽省教育厅自然科学研究项目(批准号:KJ2016JD11,KJ2018A0510);安徽省自然科学基金(批准号:1808085MF206)资助的课题~~

摘　　要：近年来,螺旋波等离子体源在核聚变条件下等离子体与材料的相互作用方面具有十分重要的研究意义.本文对高密度螺旋波等离子体原型实验装置(helicon physics prototype experiment, HPPX)中的螺旋波系统发射天线进行了优化设计,利用HELIC程序,对螺旋波的耦合和功率沉积与天线的类型、天线长度、运行频率等关键参数的相互关系作了数值模拟计算,进而给出了天线的最佳天线结构和物理尺寸.同时还分析了静磁场强度和轴心等离子体密度对功率沉积及其分布的影响,发现等离子体对螺旋波的吸收功率在多个静磁场和轴心密度处有不同的峰值功率点,且整体的耦合趋势随静磁场增大呈上升的趋势,而随轴心密度增大是下降的趋势;并根据这些仿真结果深入探讨了螺旋波等离子体的电离机制.为了进一步研究HPPX装置中螺旋波与等离子体耦合的问题,还给出了等离子体放电时的感生电磁场与电流密度的分布情况.本文工作可为HPPX装置上螺旋波天线设计和相关物理实验提供理论依据.Recently, helicon plasma sources have aroused the great interest particularly in plasma-material interaction under fusion conditions. In this paper, the helicon wave antenna in helicon physics prototype experiment(HPPX) is optimized. To reveal the effect of the radial density configuration on wave field and energy flow,Maxwell’s equations for a radially nonuniform plasma with standard cold-plasma dielectric tensor are solved.Helicon wave coupling and power deposition are studied under different types of antennas, different antenna lengths and driving frequencies by using HELIC. Through the numerical simulation, the optimal antenna structure and size are obtained, that is, half helix antenna, which works at 13.56 MHz and has a length of 0.4 m, can generate nonaxisymmetric radio frequency energy coupling to excite higher electron density.The influences of different static magnetic fields and axis plasma densities on power deposition are also analyzed. It is found that the absorbed power of the plasma to the helicon wave has different peak power points in a multiple static magnetic field and axial plasma densities, and the overall coupling trend increases with static magnetic field increasing, but decreases with axis plasma density increasing. According to the simulation results, the ionization mechanism of helicon plasma is discussed. In order to further study the coupling of helicon wave with plasma in HPPX, the induced electromagnetic field and current density distribution are given when the plasma discharges. Under parabolic density distribution, the field intensity of the induced electric field at the edge is large, while neither the induced magnetic field nor current density changes much along the radial direction, the energy is distributed evenly in the whole plasma. Under the Gaussian density distribution, the induced electric field intensity is higher at the edge, while the induced magnetic field and current density in the center are much higher than at the edge.In this paper studied are the structure and

关 键 词：螺旋波等离子体 天线 静磁场强度 轴心等离子体密度 功率沉积 

分 类 号：O53[理学—等离子体物理]