HL-2A装置ECRH系统的新天线设计

Using the principle of quasi-optic, the new antenna of the electron cyclotron resonant heating(ECRH) system on the tokamak HL-2A has been designed. After being focused by the elliptical mirror and reflected by the plane mirror, 4 68GHz/500kW/1s electron cyclotron wave beams would be injected into the tokamak from one Æ350mm port to accomplish heating to the plasma. Based on the propagating theory of the fundamental Gaussian beam, it is gotten that at the centre of the cross section of the tokamak, the power density of each beam is 158MW•m^-2, and the power density radius, which means that the power density is reduced by a factor 1/e² compared to the power density at the centre of the beam, is 31.7mm. On the mirror, due to the focusing and reflecting, the ohmic loss and diffraction loss of the microwave beams are 0.27% and 0.64%, respectively. By the finite element analysis software ANSYS, some thermal analysis of the mirror have been done. The result shows that the highest temperature increase would be only 0.47℃ under 1s pulse load, so there is no need of any cooling.     

The Design of the ECRH/ECCD Launcher System for the HL-2A Tokomak

Electron cyclotron resonance heating and electron cyclotron current drive （ECRH/ECCD） have developed significantly in recent years such as Tore Supra, JT-60U , Heliotron j. It has many advantages over other means of heating and current drive. Firstly, the launcher can be located far away from the plasma. Secondly, the fact that the ECRH/ECCD power can be injected as narrow Gaussian beams, giving rise to highly localized power deposition, makes ECRH/ECCD an ideal candidate for local MHD control.     

HL-2A装置ECRH系统指标介绍

在HL-2A装置上正在开展电子回旋共振加热（ECRH）项目的工程研制，系统具有1MW，68GHz，1s的微波规模。采用弱场侧O模式注入，ECRH的定域加热特性可以用于等离子体加热、电流驱动和分布控制以及改善约束等实验的物理研究。到目前为止，电子回旋共振加热的各项子系统正在设计和研制中，系统的总体物理和工程参数已经初步确定，在此对其作一介绍。     

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应用准光学原理设计了HL-2A装置电子回旋共振加热(ECRH)系统新的集束天线,该天线能使4束68GHz/500kW/1s电子回旋波通过椭球镜聚焦和平面镜的反射,从一个直径350mm装置窗口同时注入托卡马克,对等离子体实现加热。根据基模高斯束的传播原理得出,在装置环向横截面中心处单条波束的功率密度为158MW•m-2,功率密度降为中心密度的1/e2的半径为31.7mm,微波束经过镜面聚焦和反射产生的欧姆损失和衍射损失分别为0.27%和0.64%。利用有限元分析软件Ansys对镜面进行热分析得到,在1s脉冲载荷下最大镜面温升仅为0.47℃,镜面可以自然冷却。     

HL-2A装置ECRH传输系统的概念设计

HL-2A装置将建造一个75GHz／1 MW／1s的ECRH系统。本文介绍了由传输线和水平天线构成的传输系统的概念设计(见图1)。详细介绍了系统的主要部件：波导，椭球镜，CVD窗(见图2)和可调节的平面镜。对天线的新设计能使波束极向可调，使得能量能沉积在不同区域。     

Superconducting Magnet of the Gyrotron for HL-2A ECRH System

In order to carry on ECRH experiments and research on HL-2A tokamak, two sets of 4 mm gyrotrons were imported from GYCOM. Each of them has a superconducting magnet system to offer a required magnetic field configuration. In gyrotron, a strong magnetic field is necessary for electron beam to satisfy the electron cyclotron resonance condition and to excite one the eigemodes in the cavity. Its functions are： （I） to make electrons gyrate, （ 2 ） to offer enough adiabatic compression value to make electrons acquire strong transverse energy. During the period of adjustment, magnetic field distribution was measured. Meanwhile, operating current of superconducting magnet and operating frequency of gyrotron were determined.     

HL-2A 装置ECRH天线系统的结构设计

HL- 2A 装置电子回旋共振加热的天线系统主要由天线外壳、椭球镜、平面镜、转动机构和推动机构组成。转动机构可以推动平面镜环向、极向转动, 进行不同区域的等离子体的加热和电流驱动。平面镜环向转动的角度范围为0°~ 37°, 极向转动的角度范围为0°~ 15 °。给出了驱动杆与平面镜转动角度之间的关系和对应曲线。介绍了椭球镜的安装和推动机构的结构, 给出了椭球镜的椭球面方程。整个天线系统结构紧凑, 安装和拆卸容易, 调节方便。     

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.     

HL-2A装置ECRH高压电源分析计算和模拟仿真

HL-2A装置电子回旋共振加热系统主要由4只68GHz，550kW，脉宽1s，管体接地，阴极电压-55kv，阳极电压25kV，电流25A的回旋管组成。本文介绍的ECRH高压电源是同旋管的主高压电源，它主要用于加速束电流，提供直流输入功率．主高压电源的稳定对有效地提高回旋管的电功率与微波功率的转换效率起着重要的作用。     

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-2A装置真空监测系统的研制

HL-2A装置是我国第一个具有轴对称（极向）偏滤器位形的大型托卡马克装置。其真空系统的工作特点是长时间连续的不间断运行，实验人员值班时间过长，极易产生疲劳，在这种状况下很容易发生事故，并且在放电实验期间会产生辐射，因此在进行放电实验时，装置大厅内不允许人员进入，所以有必要设计一套远程自动化监测系统放在装置大厅外，使值班人员在友好的人机界面下，实时完成对装置真空状态和现场真空设备的监视，这样既能增加装置的安全性和真空系统的可靠性，同时也能减轻值班人员的劳动强度。本文详细介绍了该系统的设计和应用过程。     

HL-2A装置3MW 68GHz ECRH系统调试与运行

HL-2A装置3MW ECRH系统采用双高压电源形式的电子回旋管,阴极高压电源为回旋管提供加速束电流,阳极高压电源对通过转换区后的束电流施加减速作用,利于回旋管收集极吸收。根据回旋管运行特点和各回旋管不同的工作特性,合理优化回旋管阴极、阳极高压电源工作电压和其他参数。通过远程监控系统,使同时工作的回旋管处于较好的工作状态,充分提高HL-2A装置ECRH系统多管运行的微波输出功率。实验中,6支回旋管同时运行时,微波最高输出功率2.5MW,达到设计额定值83%,使HL-2A装置中等离子体得到了有效的加热。     

The Real-Time Arc Protection Circuit for ECRH on HL-2A Tokamak

In 2005 year, SWIP carded through a general engineering and physics experiment of ECRH on HL-2A tokamak. The ECRH protection system is studied and set up to insure the security of ECRH system, and the work is normal. The main protection object of all ECRH system is the gyrotron, and the arc protection for it is more important in the protection system.     

HL-1M装置ECRH系统的研制与实验

在HL-1M装置上研制了一套75GHz、500kW／50ms的大型电子回旋共振加热系统，设计了准光学传输系统和顶部、水平两套天线，对系统进行了调试，获得了最佳的系统参数和运行条件，并开展了各种O模和X模实验。在单管250kW的基波0模的实验中，获得电子温度提高40％，电流位形负剪切分布以及鱼骨模不稳定性研究等重要的物理实验结果。     

HL-2A装置等离子体可见光成像系统

为了配合HL-2A装置的工程联调和首次等离子体放电，需要一种可靠和直观的诊断手段，以确认产生了所谓的“First plasma”(初始等离子体)放电。为此我们研制了一套新的诊断系统，即等离子体可见光成像。等离子体成像是近年来发展起来的一项先进诊断手段。目前在托卡马克装置上广泛采用。     

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.     

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HL-2A装置3MW ECRH系统采用双高压电源形式的电子回旋管,阴极高压电源为回旋管提供加速束电流,阳极高压电源对通过转换区后的束电流施加减速作用,利于回旋管收集极吸收。根据回旋管运行特点和各回旋管不同的工作特性,合理优化回旋管阴极、阳极高压电源工作电压和其他参数。通过远程监控系统,使同时工作的回旋管处于较好的工作状态,充分提高 HL-2A 装置 ECRH 系统多管运行的微波输出功率。实验中,6支回旋管同时运行时,微波最高输出功率2.5MW,达到设计额定值83%,使HL-2A装置中等离子体得到了有效的加热。     

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.     

HL-2A装置低杂波保护系统研制

1995年以来在HL-1M装置上成功地进行了LHCD实验，取得了丰硕的成果。2004年的LHCD实验是在HL-1M装置基础上改进的HL-2A装置上进行的。保护系统的优化是LHCD系统提高与完善的重要内容之一。LHCD微波功率传输系统的波导天线内部拉弧打火探测及其保护系统，微波功率输出系统速调管的管体电流定量测量及其保护系统都是本年度实验的重要项目。