托卡马克中极向静电天线的离子Bernstein波的耦合计算

本文采用均匀的等离子体模型,对在托卡马克低场边由极向静电天线激发离子Bernstein波(IBW)的耦合问题作详细的理论分析。为了能更符合实验中的实际情况,文中考虑天线为有限长度以及非零的极向波数(k_y≠0)对耦合特性计算的影响。计算表明,极向静电天线可以有效地在等离子体中激发IBW。比较该天线与传统的环向IBW天线的辐射功率谱和阻抗等计算结果,表明两种天线对IBW的耦合有相似的特性。 关键词：     

HT-7托卡马克中低杂波和离子波恩斯坦波协同作用的数值研究

用隐含5点模式对二维Fokker-Planck方程进行离散化,调用NAG程序库中子函数D03UAF求解该方程,并将求解二维Fokker-Planck方程的code与波的射线轨迹code相结合,根据HT-7托卡马克装置参数,分别对有或没有IBW情况下的等离子体电流的全波驱动和在低杂波和离子伯恩斯坦波协同作用下低杂波的功率沉积分布、驱动电流分布等进行数值模拟研究.结果显示:有IBW情况下的全波驱动电流分布比没有IBW时全波驱动的电流分布区域要广一些,而且驱动的总电流也大一点;在双波协同作用下,全波驱动的等离子体电流空间分布随IBW的频率和n_//谱的变化而变化;在两波协同作用下低杂波驱动非感应电流的效率得到了很大的改善.     

KT-5B托卡马克装置上离子伯恩斯坦波激发条件的实验研究

本文介绍了在KT-5B托卡马克装置上,线性离子伯恩斯坦波的激发与边缘离子密度涨落、托卡马克放电参数以及发射天线位置之间关系的实验研究结果。实验表明,边缘离子密度涨落过大,将使离子伯恩斯坦波激发变得困难;正常的托卡马克运行的放电参数范围与有效激发离子伯恩斯坦波的参数范围一致;对纵环电流天线,可能存在静电模转换激发和直接激发这两种离子伯恩斯坦波激发方式共存的情况。 关键词：     

托卡马克等离子体的快波模转换和吸收

本文对托卡马克位形,用动力理论研究了非均匀热等离子体的ICRF快波模转换及有关的阻尼机制。结果表明,对于多种离子成分的等离子体,在离子-离子混杂共振层和二次谐波回旋共振层附近,存在快波和离子伯恩斯坦波(IBW)之间的模转换;模转换层附近的色散关系与k_(?),离子种类浓度以及等离子体密度有明显的相关性。适当选择这些参数可大大改善快波能量的吸收和吸收的局域性。而在一种离子成分的等离子体中、无模转换过程发生。     

HT—6B等离子体对金属玻璃的辐照效应

金属玻璃是由熔态经急冷淬火形成的非晶态金属,具有很高的力学强度和良好的抗腐蚀、耐辐照性能。关于中子、质子、电子和He、Ar离子等分别对金属玻璃的辐照损伤效应已有一些研究报道。托卡马克装置中的等离子体辐照是一种十分复杂的过程,它包括有质子、电子、光子、氘核和少量杂质重离子与中性粒子的混合辐照。本工作研究了某些金属玻璃在托卡马克装置真空器壁处经等离子体辐照以后的结构变化,探索金属玻璃用于托卡马克核聚变装置真空器壁的可能性。     

振镜法测量等离子体离子温度

 离子温度是托卡马克等离子体一个重要参数，介绍了一套振镜扫描装置，该装置主要由0.5m单色仪和安装在出射狭缝前的振动的石英镜片组成，时间分辨率小于10ms，系统测量误差小于20eV。测量了HT-6M托卡马克CV(227.1nm)谱线的线形，并由谱线的多普勒展宽得出欧姆加热和离子回旋共振加热（ICRH）下的离子温度，结果表明ICRH期间离子温度由200eV升高到300eV。这套装置广泛应用在中小型托卡马克上。     

光谱仪器

TH744 2004064059 振镜扫描光谱仪用于托卡马克等离子体谱线轮廓测量=Measurement of spectral profiles in Tokamak plasma with an optical scanner spectrometer[刊,中]/林晓东(深圳大学师范学院物理教育系.广东,深圳(518060)),蔡红红…∥光电子·激光.—2004.15(4).—502-504 利用自行研制的振镜扫描光谱仪在HT-7托卡马克装置上建立起光谱线轮廓诊断系统,并对等离子体离子温度和H/D含量比进行测量。实验结果表明.HT-7托卡马克等离子体内,OⅡ(441.60nm)和D_(?)(656.10nm)     

ITER装置中等离子体旋转和反馈控制对电阻壁模影响的数值研究

在托卡马克等离子体中,电阻壁模是非常重要的磁流体不稳定性,特征时间在毫秒量级.对长时间稳态运行下的先进托卡马克,电阻壁模限制着聚变装置的运行参数空间(放电时间和比压),影响经济效益,所以研究电阻壁模稳定性至关重要.本文使用MARS程序,针对ITER装置上9 MA先进运行平衡位形,研究了等离子体旋转和反馈控制对电阻壁模的...     

基于EAST束发射光谱的中性束衰减特征研究

中性束注入(NBI)是托卡马克装置重要的辅助加热与电流驱动手段,中性原子的离化是决定中性束的加热(能量和粒子沉积剖面)和电流驱动效率的关键环节。通常情况下,利用背景等离子体参数与中性束参数模拟计算快的中性粒子与等离子体的离化,即中性束沉积过程,进而分析托卡马克中性束加热和电流驱动效果。束发射光谱是高能中性粒子注入等离子体后,与等离子体的电子、离子发生碰撞激发,中性粒子退激发过程中产生的一系列特征谱线,其束发射光谱强度受等离子体密度、温度、束能量、束密度等因素影响,可以利用束发射光谱强度变化研究中性束的衰减特性。在EAST托卡马克上通过实验测量中性束粒子与等离子体碰撞激发的光谱强度,分析得到了中性束在不同等离子体密度以及不同中性束能量下的衰减特性,并采用主动束光谱仿真与数值分析软件(SOS)进行了相应的模拟计算,研究表明实验测量与模拟计算结果两者具有较好的一致性,这验证了通过实验测量束发射光谱获取中性束衰减特征的可行性。     

聚变崩坍

一个类似于儿童玩具的沙堆崩坍模型是一种可用于研究如何使核聚变装置托卡马克 (Ｔｏｋａｍａｋ)达到最佳条件的工具 ,托卡马克是一种利用核聚变反应来获取能量的装置 .为了能实现获取能量这个目的 ,第一步是要在托卡马克装置中得到高温、高密度的等离子体 ,特别是一种称为Ｈ -模的最好位形 .但到现在为止 ,我们还不很清楚如何能使等离子体达到这种状态 .沙堆模型为这方面的研究提出了一些有益的启示 .美国沃里克大学 (ＷａｒｗｉｃｋＵｎｉｖｅｒｓｉｔｙ)的Ｓ .Ｃｈａｐ ｍａｎ教授设计了一个模拟沙堆崩坍的计算机模型 ,他是利用调节沙粒…     

Study of Electron Heat Pulse Propagation and Particle Diffusion During the Synergy of LHW and IBW Heating in the HT-7

A successful experiment on lower hybrid wave (LHW) and ion Bernstein wave (IBW) synergy has been carried out in the HT-7 superconducting tokamak. With 560KW of LHW heating power and 160 KW of IBW heating power, during the synergy of the LHW and IBW experiment we achieved an improved plasma: the electron density increased and peaked, the soft X intensity increased too. A five-channel far-infrared (FIR) hydrogen cyanide (HCN) laser interferometer was used to measure the electron density profile. The particle diffusion coefficient was studied for the experiment, and the result compared with the heat diffusion coefficient. With the same injected LHW and IBW power, high electron density n_e can deduce the electron pulse propagation and the particle diffusion.     

Study of Density Behavior During LHCD and IBW Heating in the HT-7 Superconducting Tokamak

A new method using special shape parameters has been introduced to study density behavior with synergy of lower hybrid current drive (LHCD) and ion Bernstein wave (IBW) heating in the HT-7 superconducting tokamak. During the synergy of the LHCD and IBW heating an improved confinement plasma was achieved, and the electron density was increased and peaked.     

Generation of cyclotron harmonic waves in the ionosphericmodification experiments

In the present paper, the parametric decay instability of the pump X-mode into electron Bernstein wave (EBW) near second harmonics of electron cyclotron frequency and IBW at different harmonics (ωci; n=2,3,4) is examined. Expressions are derived for homogenous threshold, growth rate and convective threshold for this instability. Applications and relevances of the present investigation to ionospheric modification experiment in the F-layer of the ionosphere as well as during intense electron cyclotron resonance heating in the upcoming MTX tokamak have been given     

边界高密度下低杂波耦合的数值模拟

采用STEP＋RAMP的模型模拟低杂波与等离子体耦合。在该模型中,等离子体边界密度一开始就处于一个比较高的值(大于截     

H模式放电中等离子体边界附近的漂移波不稳定性

本文从一简单模型出发,研究了H模式放电中边界附近的漂移波不稳定性。发现由于H模式放电中边界密度梯度很大,磁剪切的稳定作用变得不重要,漂移波不稳定性可以在边界附近发生,并可能成为宽频带密度涨落的原因。来自中性束加热的高能离子与漂移波的共振,则可能解释准相干涨落。     

离子伯恩斯坦波对低杂波驱动电流影响的研究

利用改进的二维Fokker-Planck方程和低杂波射线轨迹程序研究了在低杂波和离子伯恩斯坦波协同作用下低杂波的功率沉积分布、驱动电流分布。数值结果显示在两波协同作用下低杂波驱动非感应电流的效率得到了很大的改善。     

Study on modulation of near infrared radiation based on plasma photonic crystal

In this paper, a plasma photonic crystal (PPC) for infrared radiation modulation which is composed of indium tin oxide (ITO) and plasma is proposed. The performance of plasma photonic crystal in near infrared radiation modulation is researched by transfer matrix method (TMM). The simulation results show that the near infrared radiation pass band can be adjusted by the changing of plasma frequency of plasma. The reflection to near infrared radiation by plasma photonic crystal increases with plasma frequency and that of absorption decreases. In addition, the modulation performance of the plasma photonic crystal at different incidence wave angles is also studied. The results show that the incident wave angles have little effect on the transmission of plasma photonic crystal in near infrared band. The reflection of the plasma photonic crystal to near infrared radiation decreases with increasing of the incident wave angle, but that of the absorption increases with the incident wave angle. Therefore, the proposed plasma photonic crystal has a potential application in tunable near infrared filter devices.     

Unmagnetized sheath waves

Plasmas bounded with metal walls have sheaths at their edges near the walls, along which electrostatic waves may propagate. We build on a long history of dielectric-bounded plasma waves, e.g., relating transverse (or series) resonances to cut-off frequencies of our sheath waves. We present kinetic simulations (PIC-MCC), confirming the dispersions and that the edge waves perturbed densities and potentials are largest at the edge; those of the body waves are largest in the body, all as if the two sets of waves are guided along their respective regions.We also drive edge waves sufficiently strongly to cause electron heating producing ionization of the background gas, which maintains a plasma discharge. The heating profiles and density scaling of these resonant surface wave discharges differ markedly from the well known capacitive, inductive, and wave-coupled discharges.