The ECRH Transmission System for HL-2A Tokamak

Electron cyclotron resonance heating and electron cyclotron current drive （ ECRH/ECCD ） have been developed significantly in recent years in many devices such as Tore Supra, JT-60U, Heliotron J. It has many advantages over other means of heating and current drive. The EC power can be injected as narrow gaussian beams, giving rise to so highly localized power deposition as to make ECRH an ideal candidate for local MHD control.     

The Introduction to the ECRH System of the HL-2A Tokamak

The 1 MW/68 GHz/1 s ECRH system of HL-2A device is being designed or fabricated. The O mode wave beams are injected into plasma from low field side of the HL-2A tokomak. Because the EC wave can heat plasma locally, it is a very versatile scheme which has been employed to heating, current drive, profile control, confinement improvement. Up to now, the basic physical and engineering parameters of the whole system have been fixed and the subsystems are being designed or fabricated.     

辅助加热下HL-2A边界层等离子体数值模拟

以二维边界等离子体流体模拟代码B2.5为核心,编制适合于具有封闭偏滤器位形特征托卡马克的边界层网格划分代码和计算后处理代码.模拟分析HL-2A托卡马克有约3MW辅助加热功率时的边界等离子体特性.结果表明,偏滤器靶板前形成了致密低温等离子体,偏滤器运行于高再循环状态.     

Theoretical Study of ECRH Heating Of HL-2A Tokamak Plasma

Electron cyclotron resonance heating （ECRH） is one of the main auxiliary heating schemes for the HL-2A tokamak. Routinely, the ohmic heating can provide a heating power about 300-450 kW in this device （ estimated from that the total toroidal current is about 300 kA while the totoidal voltage is 1-1.5 V）. The total power for the ECRH now is 1 MW and in future 2 MW.     

The Analysis and Calculation on ECRH Anode Circuit on the HL-2A Tokamak

In the last year, ECRH system has been built in the HL-2A and the testing of gyrotron is also finished. In the project testing, one of the problems is current-peak occurring in the anode circuit of gyrotron. The current-peak is much larger than that of the value set in protection circuit. The frequent current-peak frequently occurring in the rising of anode-voltage often caused the protection circuit to mistaken trigger. The mistaken triggering often halted the normal gyrotron-testing. A set of equations of anode circuit are derived for analysis the phenomena of the current-peak. The calculation based on the deduced formula shows that value of the current-peak strongly depends on the inductance L, capacitance C and the ramp-time of anode voltage in the anode circuit. The conductance L and capacitance C are the characteristic inductance and capacitance of the cable that is used for anode HV power supply. The numerical calculation is exactly consistent with waveform of the current peak recorded by oscillograph, that means the derived formula are correct. In order to decrease the value of the current-peak, we should decrease capacitance C, and increase inductance L and ramp-time of anode voltage.     

Primary Results of ECRH Experiment and Electron Heat Transport on the HL-2A Tokamak

As an ordinary mainly auxiliary heating on tokamak plasma, electron cyclotron resonance heating （ ECRH ） is an useful method to the study of electron heat transport and confinement performance. In this work, primary results of ECRH experiments on the HL-2A tokamak are presented. The features of confinement and electron heat transport during ECRH are analyzed.     

HL-2M装置中性束注入加热系统研制进展

为开展磁约束堆芯燃烧等离子体物理实验,正在建造的HL-2M装置拟建造3条5 MW的中性束注入加热束线。简要概述了HL-2M装置NBI加热系统的总体规划,第1条5MW-NBI加热束线的设计,离子源调试实验,注入器核心部件的安装和测试结果。通过调试,目前单个离子源引出束流达到36 A,加速电压75 kV,离子束功率达到2.4 MW,脉冲宽度3 s。通过测试发现：注入器的4条离子束汇聚角误差小于±0.1°,残留离子偏转磁体的磁场测试值与模拟计算值偏差小于±5%,注入器静态真空值达到1.0×10^-3 Pa。注入器采用大型非标低温泵,低温泵的抽速达到2.40×10⁶ L/s。第1条5MW-NBI加热束线的试装和测试结果表明,该束线能够满足HL-2M装置NBI加热的技术要求。     

Vacuum System for HL-2A Tokamak

The vacuum system of today＇s tokamak devices is designed to meet the operational requirements of the experiments. The operation can be divided into five modes, （1） pumping down and leak detecting of the vacuum vessel, （2） baking, （3） plasma-facing component （PFC） conditioning, （4）evacuating and controlling of the particles at plasma edge, （5） plasma discharge experiments.     

HL-2Aװ��ECRHϵͳ����Ч�ʵIJ����о�

介绍了HL-2A装置ECRH系统传输效率的测量方法。通过对MOU、回旋管输出窗口及真空密封窗口吸收功率的测量,得到HL-2A电子回旋系统的传输效率为90％左右。提出了除由MOU处测量微波功率外,可以由传输线的其他部位确定功率的方法。     

HL-2A Tokamak Experiment Data System

HL-2A tokamak experiment data system （ HL-2A EDS ） consists of an experiment network, various of dada acquiring sub-systems, a great deal of realtime data processing applications, a display system, a lot of interacting data analyzing workstations, a data storage system, a management platform, and a high performance computer. The system was built start in 2002, and has been modified greatly since then.     

Plasma Feedback Control System for HL-2A Tokamak

As the limit of time and budget etc, the control system of HL-2A just could be operated in programmed discharge when HL-2A was checked and accepted in 2002. Recent years, many subsystem of HL-2A have been improved in functions and performances. And the demand for experiment of HL-2A is becoming more and more higher in plasma discharge parameters. So it＇s necessary to develop a plasma feedback control system （ FBCS ） which has enough functions and good stability and reliability to satisfy the demand of experiment on HL-2A.     

HL-2Aװ��SDD��X����PHA����ʵ����

用软X射线脉冲高度分析(PHA)阵列系统获得了等离子体的电子温度剖面和电子速率分布的时间演化。测量结果表明,电子温度剖面在OH阶段较平缓,接近抛物线1.0×[1-(r/a)2]2分布;而在ECRH(功率0.8MW)阶段,等离子体中心(z＝0)电子温度上升了0.6keV,边缘(z＝30cm)处只上升了0.1keV,反映出ECRH功率沉积在等离子体中心区域;在ECRH期间有大量的高能电子产生,因而电子速率分布在ECRH期间显著改变;等离子体中心的高能电子的数量和能量都比等离子体边缘的增加更大,ECRH(～0.8MW)期间等离子体中心(z＝0)产生的高能电子的能量可达17keV。分析表明：在ECRH(纵场Bt=1.3T)放电期间,ECRH加热效果显著,ECRH的功率主要沉积在等离子体中心附近;电子温度剖面在ECRH阶段较OH阶段峰化;ECRH期间有大量的高能电子产生,电子速率分布被改变成为非麦克斯韦分布。     

汤姆逊散射技术在HL-2A装置上的应用进展

非相干激光汤姆逊散射诊断只需要假设电子速度满足Maxwell分布,测量得到的等离子体电子温度与电子密度的数据准确可靠,是托卡马克和其他磁约束核聚变研究装置上重要的诊断工具,并朝着高可靠性、高空间分辨和高重复测量频率的方向发展,其中高可靠性是前提。电子的汤姆逊散射截面很小,其总截面为σ_T=6.65×10^-25 cm²,通常使用电光调Q的Nd∶YAG激光器作为散射光源,激光脉冲宽度约10 ns、脉冲能量约3 J,用5～8通道的光谱仪对散射光谱进行测量与分析。如何对光电探测模块输出的散射脉冲进行数据采集,是激光散射诊断的关键问题之一。以前使用电流积分式的数据采集器(Q-ADCs,如CMC080模块),在一个确定的时间宽度(如50 ns)将散射脉冲信号积分在采样电容器上,从而得到散射信号的强度值,这种方法很难排除电路噪声和外来干扰。该研究通过使用高速数据采集器(纵向分辨率≥10 bits、采样频率f≥1 GS·s^-1,如V1742B模块)在包含散射信号在内的时间段(如300～500 ns)进行采集,获得散射...     

HL-2A装置ECRH水冷却系统的研制

研制了压强达0.6MPa总流量达94m3•h-1的HL-2A装置电子回旋共振加热水冷却系统,介绍了该系统的设计、水压控制和参数 测量。计算了水压降和高电压环境中水电阻,测得的回旋管阳极水回路中的漏电流小于1mA。     

HL-2M 装置 NBI 加热系统规划及束线研究进展

为满足 HL-2M 装置高约束模式及高参数实验需求,HL-2M 装置规划 3 条中性束注入(NBI)加热束线, NBI 加热功率为 15MW。第 1 和第 2 条束线是基于正离子源的 NBI 加热束线,根据中后期高参数实验状态确定第 3 条束线采用正离子源或者负离子源。本文简要介绍了 HL-2M 装置的加热束线布局和系统设计概念,综述了基于 4 套 80kV/45A/5s 离子源的 5MW-NBI 中性束加热束线的设计参数及研制进展。在物理和工程可行性简要分析基 础上,给出了采用 2 套 200kV/12.5A/10s 热阴极负离子源的 2.5MW-NBI 束线的概念设计、工程设计及技术研究进 展。      

HL-2A装置Nd:YAG激光汤姆逊散射多道测量系统

 利用Nd:YAG激光汤姆逊散射多道测量系统对等离子体多空间点的电子温度和密度进行了测量。用标准光源和电扫描单色仪构成的标定系统对散射光谱的响应系数进行了标定。给出了等离子体中心附近6空间点的温度和密度的测量结果,时间分辨率为100 ms,空间分辨率约为2.2 cm。对实验结果的不确定度进行了估计,为-12% ~ 12%。实验结果证明：系统可测量等离子体温度的空间范围为-35 ~ -3 cm,实验数据稳定可靠。     

Study of the Protection System for LHCD on the HL-2A Tokamak

LHCD experiment has been carried through in HL-1M tokamak since 1995, and the work is successful. This years the LHCD experiment would go ahead on the HL-2A tokamak that had been improved from HL-1M system.     

HL-2Aװ�ø������ȸ�ѹ��Դ����ϵͳ�������ʵ��

研制了HL-2A装置LHCD和ECRH系统使用的高压电源,其电源拓扑分别为晶闸管交流调压型和星点控制型高压电源,通过高压脉冲调制器给LHCD和ECRH系统供电,采用了波头补偿、前馈和反馈相结合的控制方法,弥补了电源拓扑本身固有的瞬态特性不足和发电机输出的不稳定性,使电源输出电压输出平顶的稳定度优于1%。介绍了高压电源的主回路结构,对高压电源的控制进行了论述,同时给出了实验结果。     

Siliconization for Wall Conditioning in the HL-2A Tokamak

The sputtering of impurities is caused by the interactions between plasma and the first wall, and the recycling of the gas affects the particle and energy transport of plasmas with a complicated mechanism in plasma operation. It is important for present tokarnaks to achieve a good confinement and high performance plasmas by means of controls of the vacuum condition, usage of low Z materials, control of the recycling of neutral particles and suppressions of the appearances and yield of impurities. For higher plasma parameters, some of the first wall of HL-2A is covered with graphite materials and carbon fiber tiles. Hence the studies on the in-situ coating application and development, and the interactions between the coating film and plasma are needed to effectively control the impurity, improve plasma confinement and achieve high performance plasma.