磁约束核聚变电子回旋系统回旋管灯丝电源设计

采用零电压开关(ZVS)移相全桥拓扑结构设计了一款带输出电压反馈的大功率回旋管灯丝电源。本文详细地叙述了本次设计电源的整体架构、重要参数的计算过程、输出电压控制电路及其优点。最后实测了样机的主要波形与关键参数,并通过老化试验验证了其稳定性。     

HT-7低杂波相控天线阵的耦合特性分析

HT-72.45GHz低混杂波系统利用相控波导阵列将微波能量耦合到等离子体中。本工作基于二维线性耦合理论,主要利用Step+Ramp的等离子体密度剖面模型,详细分析了HT-7装置上各种关键参数(如边缘密度、密度梯度、相邻主波导相位差等)下低杂波波导阵列天线的耦合特性。分析表明,通过调节主波导之间－90°～90°的相差,天线的n_∥谱可在1.93～3.15之间灵活调节;当天线口边缘密度为0.5×10¹⁸～2×10¹⁸m^-3时,波导阵天线的反射系数可保持在5%以下,方向性系数很大;主波导之间相位差的改变对波导阵的驱动效率有很大影响。     

Study and Design of a High-Frequency Interaction Cavity for a 140 GHz Megawatts Gyrotron

The gyrotron is one of the most promising high-power millimeter-wave sources for electron cyclotron resonance heating(ECRH) in controlled thermal nuclear fusion experiments.In this paper,the design of a high-frequency interaction cavity of a 1 MW/140 GHz gyrotron is described in detail.The cavity is designed by using eigen mode analysis and radio frequency(RF) behavior calculation.Rounded transitions at the input and output tapers are designed for reducing mode conversion.With the obtained cavity structure,non-linear self-consistent equations are adopted to calculate its output power and efficiency.A particle-in-cell(PIC) method is used to simulate the beam-wave interaction process for obtaining the resonant frequency and output power of the cavity.The PIC simulation results match considerably well with the results obtained by the non-linear self-consistent calculation.The cavity is currently under construction and will be integrated with other components for overall testing.     

915 MHz TE10-TE01模式转换器设计

本文设计了一种可实现矩形波导TE10模式转换为圆波导TE01模式的转换器,用于电子回旋共振(ECR)技术薄膜沉积,使微波功率以特定模式分布在反应腔中与磁场共同作用产生等离子体,并由磁控管输出的微波中心频率为915 MHz。在满足工作带宽要求的基础上尽量提高转换效率,抑制噪声模式。通过三维仿真软件HFSS对结构进行优化,在915 MHz中心频率处转换效率达到99.90%,在中心频率20MHz范围内转换效率达到99.00%,能够满足磁控管工作频率在915 MHz下的带宽要求。     

Design of High-power Microwave Waveguide Divider

1. IntroductionHigh-power divider plays an important part inmany fields, such as military affairs, civil affairs, scientific research. In a longpulse tokamak plasma dis-charge, Lower Hybrid Wave (LHW) is a very effectivemeans fOr current driving. According to the con-struction plan of tokamak HT-7U, a twcrowave sys-tem fOr Lower Hybrid Current Drive (LHCD) will bebuilt up, in which a power divider is required to splitthe 100 kW microwave power at a frequency of 2.45GHz into two equal …     

3.7GHz大功率3db功分器设计

设计了一种用于3.7GHz低杂波电流驱动（LHCD）系统的高功率3db功分器。论文基于奇偶模理论和S参数矩阵分析,得到初步的3db功分器结构参数,然后利用高频仿真软件HFSS进行结构仿真和参数优化,得到最优结构,使得3db功分器的VSWR=1.02、D=35db、C=3.03db、I=38.2db。同时详细分析了大功率下的热损耗情况,提出了合理的散热方式,保证了功分器在长脉冲大功率时,表面平均温度处于63℃的平衡状态。     

高功率长脉冲环行器温度补偿器设计

为了保证高功率环行器在长脉冲运行时的温度稳定性,设计并实现了以PIC18F44J11单片机为控制核心的环行器温度补偿器,温度补偿器采集温度信号,根据温度补偿算法计算得到所需电流并调节输出电流大小。测试表明:在10~35℃的环境温度下、输入功率从0~250 k W范围内,温度补偿器补偿效果明显。     

A Study of Energy Conversion Efficiency Versus Plasma Density by Lower Hybrid Current Drive in HT—7 Tokamak

Ramp-up experiments by means of lower hydrid wave on HT-7 superconducting tokamak have been performed and analyzed.A ramp-up rate of over 300kA/s is obtained and a conversion efficiency of over 10% has been achieved during the ramp-up phases.The study of the dependence of conversion efficiency on plasma density shows that the conversion efficiency is affected by the driven current,which is mainly dominated by the competition of impurity concentration with wave accessibility condition.In addition,the effect of current profile may play an important role in determining the conversion efficiency.     

Development and Preliminary Commissioning Results of a Long Pulse 140 GHz ECRH System on EAST Tokamak(Invited)

A long pulse electron cyclotron resonance heating(ECRH)system has been developed to meet the requirements of steady-state operation for the EAST superconducting tokamak,and the first EC wave was successfully injected into plasma during the 2015 spring campaign.The system is mainly composed of four 140 GHz gyrotron systems,4 ITER-Like transmission lines,4 independent channel launchers and corresponding power supplies,a water cooling,control &inter-lock system etc.Each gyrotron is expected to deliver a maximum power of 1 MW and be operated at 100-1000 s pulse lengths.The No.1 and No.2 gyrotron systems have been installed.In the initial commissioning,a series of parameters of 1 MW 1 s,900 k W 10 s,800 k W 95 s and650 k W 753 s have been demonstrated successfully on the No.1 gyrotron system based on calorimetric dummy load measurements.Significant plasma heating and MHD instability suppression effects were observed in EAST experiments.In addition,high confinement(H-mode)discharges triggered by ECRH were obtained.     

Design and Test of an Antenna Module Mock-Up for the EAST 4.6 GHz LHCD Launcher

The launcher of the 4.6 GHz lower hybrid current drive (LHCD) system for the Experimental Advanced Superconducting Tokamak (EAST) consists of 24 antenna modules, each composed of an array of 3 (row) × 8 (column) waveguides. In order to verify the radio frequency (RF) design and the feasibility of the manufacturing process, a mock-up of the module has been fabricated and measured. The measured return losses of all three input waveguides are less than 25 dB at a frequency of 4.6 GHz. The transmission coefficients from the input waveguide to the output waveguides are 9.13 ± 0.2 dB and the insertion loss is 0.104 dB. These good results mean that the design method of the antenna module can be used for the new 4.6 GHz launcher on EAST. The detailed design of the multi-junction antenna module and its initial test result are described in this paper.