KTX反场箍缩装置纵场线圈结构设计与电磁分析

KTX反场箍缩装置的主要参数介于RFX装置与MST装置之间。反场箍缩的外加纵场需跟随等离子体电流的演化而变化,同时由于RFP中的磁面对于外部特别是等离子体边界处的径向磁场较敏感,所以需外部线圈的磁场更加精细,这对于线圈的磁场分布、误差场以及波纹度等的设计提出了更高的要求。根据KTX物理目标参数要求,提出矩形和楔形截面纵场磁体线圈设计方案,借助有限元软件和程序分析了其电磁场空间分布和结构受力大小。结果表明,6.4°楔形截面方案相比矩形截面方案在控制误差场方面更具有可行性。     

KTX反场箍缩装置主支撑结构设计与分析

KTX反场箍缩实验装置主支撑由柔性支撑和支撑平台组成,主要用来支撑真空室、导体壳和纵场线圈的重量。鉴于主支撑结构的重要性,通过有限元分析和理论分析相结合的方法对主支撑进行了强度分析和稳定性分析,给出了主支撑应力分布和变形情况及不同结构参数下的临界载荷。分析结果验证了主支撑结构的可行性,并为主支撑的后续优化设计提供理论依据。     

Design of the poloidal field system for KTX

The design of the poloidal field (PF) system includes the ohmic heating field system and the equilibrium (EQ) field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the poloidal and plasma currents, especially the eddy current in the stabilizing shell, yields design difficulties. The effects of the eddy current in the stabilizing shell on the poloidal magnetic field also cannot be ignored. A new PF system design is thus proposed. By using a low-μ material (μ=0.001, ε=1) instead of a conductive shell, an electromagnetic model is established that can provide a continuous eddy current distribution on the conductive shell. In this model, a 3D time-domain problem with shells translates into a 2D magnetostatic problem, and the accuracy of the calculation is improved. Based on these current distributions, we design the PF system and analyze how the EQ coils and conductive shell affect the plasma EQ when the plasma ramps up. To meet the mainframe design requirements and achieve an efficient power-supply design, the position and connection of the poloidal coils are optimized further.     

Capability Assessment of the Equilibrium Field System in KTX

Radial equilibrium of the KTX plasma column is maintained by the vertical field which is produced by the equilibrium field coils.The equilibrium is also affected by the eddy current,which is generated by the coupling of copper shell,plasma and poloidal field coils.An equivalent circuit model is developed to analyze the dynamic performance of equilibrium field coils,without auxiliary power input to equilibrium field coils and passive conductors.Considering the coupling of poloidal field coils,copper shell and plasma,the evolution of spatial distribution of the eddy current density on the copper shell is estimated by finite element to analyze the effect of shell to balance.The simulation results show that the copper shell and equilibrium field coils can provide enough vertical field to balance 1 MA plasma current in phase 1 of a KTX discharge.Auxiliary power supply on the EQ coils is necessary to control the horizontal displacement of KTX due to the finite resistance effect of the shell.     

A Consideration on Increasing Current Density in Normal Conducting Toroidal Field Coil for Spherical Tokamak Power Plant

The center post is the most critical component as an inboard part of the toroidal field coil for the low aspect ratio tokamak. During the discharge it endures not only a tremendous ohmic heating owing to its carrying a rather high current but also a large nuclear heating and irradiation owing to the plasma operation. All the severe operating conditions, including the structure stress intensity and the stability of the structure, largely limit the maximum allowable current density. But in order to contain a very high dense plasma, it is hoped that the fusion power plant system can operate with a much high maximum magnetic field BT ≥12 T-15 T in the center post. A new method is presented in this paper to improve the maximum magnetic field up to 17 T and to investigate the possibility of the normal conducting center post to be used in the future fusion tokamak power plant.     

Preliminary Design of GDC System for KTX Device

KeDa Torus for eXperiment (KTX) is a reversed field pinch magnetic confinement fusion research device whose main parameters are between in the RFX and MST. The base vacuum of KTX is 1 × 10^?6 Pa. Six sets of turbomolecular pumps parallel installed in the six horizontal ports which served as the main pumping system for KTX and the diameters of the ports are 0.15 m. Before plasma discharge, glow discharge cleaning (GDC) system is applied to clean C, O and hydrocarbon impurity on the vacuum vessel (VV) surfaces of KTX. An inflation system and residual gas analyzer system are designed to supply the working gas and monitoring the effect of GDC respectively. According to the GDC experiment practice, the working gas pressure of the KTX GDC system is designed as 0.3 Pa, with average current density of 0.15 A/m². Two sets of the GDC probes are installed in KTX horizontal ports symmetrically with interval angle of 180º and the input current of each anode is 1.6 A. According to the current density distribution, the centre of the VV cross section is the superior working area for GDC anode, a screw-nut pairs with the cooperation of bellows can transfer the anode from its storage position to its working position, and the stroke of the screw-nut pairs is 0.5 m. Based on the temperature rise calculation, the maximum equilibrium temperature of the anode during glow discharge is about 275 °C (under 200 °C baking). The thermal stresses caused by the temperature distribution on the anode’s components especially in the vacuum brazing areas are inspected during GDC process. All the simulation results show that the structure and base material of the KTX GDC anode can work normally without additional active cooling system.     

Numerical analysis of MD events and preliminary thermal calculation for KTX vacuum vessel

KTX is a new reversed field pinch (RFP) magnetic confinement device which is under design in ASIPP and USTC. Major disruption (MD) events may occur in future operating process, which is simulated with the finite element (FE) method. The results present that the peaks of eddy currents on vessel and conductor shell are respectively 11.791 kA and 68.637 kA with maximum stress 67.1 MPa due to high transient electromagnetic (EM) force. It is confirmed that the structure is still strong enough to bear the electromagnetic loads even if the worst case. Besides, as KTX vacuum vessel will take the method of natural cooling for heat dissipation during plasma discharge (0.5–1.0 MA), a preliminary thermal calculation was implemented in normal condition to decide suitable time parameters such as duration and interval. It is suggested that the discharge interval should be no less than 5 min for the complete 1 MA plasma with 100 ms duration, which can guarantee the temperature of vacuum vessel below 200 °C.     

Excitation and Propagetion of Modified Fluctuation in a Toroidal Plasma in KT—5C Device

Understanding the propagation of the turbulent perturbation in the tokamak edge plasma is an important issue to actively modify or control the turbulence,reduce the anomalous transport and improve plasma confinement.To realize active modification of the edge perturbation,a high dynamic output,broad-band,low-cost power amplifier is set up,and used to drive the active probes in the experiments on KT-5C Tokmak.By using small-size magnetic probes together with Langmiur probes,It is observed that the modified perturbation by the active probes with sufficiently driving power may spread with electrostatic mode,and electromagnetic mode as well.     

Integrated Design System of Toroidal Field Coil for CFETR

Integrating engineering software is meaningful but challenging for a system code of a fusion device.This issue is seldom considered by system codes currently.Therefore,to discuss the issue,the Integrated Design System of TF Coil(IDS-TFC) has been worked out,which consists of physical calculation,CAD,and Finite Element Analysis(FEA).Furthermore,an Integrated and Automatically Optimized Method(IAOM) has been created to address the integration and interfaces.The method utilizes a geometry parameter to connect each design submodule and achieve automatic optimization.Double-objectives optimization has been realized,confirming it is feasible to integrate and optimize engineering design and physical calculation.Moreover,IDSTFC can also serve as a useful reference of integrated design processing for subsequent fusion design.     

二极铁磁场一阶和二阶梯度指数修正

本文采用表面修正线圈对二极铁磁场一阶（α线圈）和二阶（β线圈）指数进行修正。当分别通电流I=3A时,α=0.052、β=0.27。实验结果与理论设计符合得很好,α值相差约1%,β值相差约2%。     

On the Transition Regime of Nonlinear Error Field Penetration in Toroidal Plasmas

The error field penetration is numerically studied in the frame of the visco-resistive magnetohydrodynamics(MHD) model.A transition scaling is obtained to link the Rutherford and Waelbroeck regimes in the nonlinear phase of error field penetration process.Furthermore,a transition density scaling of[b_r/B_T]_(crit)~n_e~(1/2) obtained in accord with recent experimental observations in the J-TEXT tokamak.     

单脉冲磁场精确设定装置的研制

本文介绍了一种用于磁镜装置研究中脉冲磁场精确设定的装置，其重复精度误差小于１／１０００。     

Preliminary Engineering Design of Toroidal Field Magnet System for Superconducting Tokamak HT-7U

1.IntroductionHT-7Usuperconductingtokamakisanationalsci-entificresearchprojectofChina.ThislargefusionexperimentaldevicewillbebuiltinthelnstituteofPlasmaPhyslcsofChineseAcademyofSciences.ThemissionofHT-7Uistodevelopthescientificba-sisforacontinuouslyoperatingtokamakfusionreac-tor,achievingasteadystateandanextremelylongpuIseoperatlonwlthhigh-betadouble-null,aswellassingle-nullplasmasatfllllcllrrent.HT-7Uisafullsuperconductingtokamakdevlce.ltstoroidalfieldsystemisoneoftheimportantpartsofthe…     

基于现场可编程门阵列的数字调节器设计

根据磁铁稳流电源闭环控制的基本原理,将模拟调节器及相关的外围控制电路采用全数字化控制技术,并通过嵌入数字信号处理模块的现场可编程门阵列（FPGA）来实现,设计了数字调节器（DRL）。通过样机试验证明,该数字调节器可实现对电源的全数字化调节和控制,满足多数加速器对静态磁铁稳流电源的控制需求。     

大功率辐照加速器磁场系统研制

针对10MeV大功率辐照加速器研制的需求,对其磁场系统进行研制,此磁场系统由聚焦系统和扫描系统组成。根据束流加速输运的磁场要求,进行了磁场设计、模拟计算。聚焦系统由6个聚焦线圈组成,每个线圈约束磁场的径向均匀区为4cm,为加速管聚束段提供横向约束磁场,实测磁场分布与束流要求计算曲线分布基本吻合。扫描磁铁采用分体结构,扫描宽度为±334mm,最大扫描频率为15s^-1,通过优化磁极结构,使扫描均匀度达到92%。磁场系统各项性能均满足10MeV电子直线辐照加速器的技术要求并稳定运行至今。     

Design of the Control System of Toroidal Field （TF） Power Supply for J-TEXT Tokamak

J-TEXT, formerly TEXT-U at the University of Texas at Austin in USA, is a medium-sized tokamak at the Huazhong University of Science and Technology. The toroidal field （TF） power supply of this tokamak should provide a current of 160 kA and a flat duration of 500 ms for the toroidal field coils to generate a maximum toroidal field of 3 T at the geometric center of the vaccum vessel. This paper presents a design of a new control system which takes the real-time feedback control option for the TF power supply operation. The system was tested successfully during the commissioning. In the first experimental campaign of J-TEXT, the system effectively controlled the power supply to provide a fiat current up to 92.5 kA and therein the TF produced reached 1.74 T, which enabled the machine to generate the first plasma successfully.     

碳纳米管场发射X光源测控系统设计

现有的X射线源多采用热阴极,工作温度高、功耗大、不易实现多个阴极的集成和可编程控制。本实验室研制的新一代基于碳纳米管冷阴极场发射X光源系统,可以突破传统热阴极X射线源的上述缺陷,同时为CT系统实现高时间分辨,减少辐射剂量提供新的路径。针对新制备的CNT阴极场发射性能测试的需求,利用Lab VIEW软件平台设计了碳纳米管场发射X光源测控系统,该系统进行多次试验检验运行稳定可靠、自动化程度高、操作简便,能够实现对X光源的可编程控制,为稳定CNT阴极发射电流、提高阳极电压、材料老化提供可靠的测控平台。     

低温喷嘴装置内流场的数值模拟研究

激光抑制凝聚法(CRISLA)是目前极具工业应用潜力的激光同位素分离(LIS)方法.在应用激光抑制凝聚法分离S同位素时,需要借助低温喷嘴装置获得低温过饱和S F6气体,因此该方法的实际分离性能和优化除与激光参数相关外,还依赖于低温喷嘴装置内的流动状态,为了研究低温喷嘴装置结构和设计参数对分离性能的影响规律,优化分离性能...     

Test and Analysis of China's First Short Conductor Sample for ITER Toroidal Field Coils

In the framework of the ITER Qualification Tests, the first China TF conductor sample (CNTF1) was tested at the SULTAN facility. The sample was made of two TF conductor sections manufactured from identical internal stannum strands provided by the Oxford Superconducting Technology Company (OST). In order to evaluate the conductor performance, the current sharing temperature (Tcs) was measured at specified electromagnetic load cycling steps. Both conductor sections of the CNTF1 sample showed identical performance. Tcs was 7.2 K before cycling loading, and 6.9 K even after 950 cycles, without significant degradation, which substantially exceeds the ITER requirement of 5.7 K. The tests of the CNTF1 conductor sample showed that the electromagnetic cyclic load exhibited a negligible effect on the conductor performance. The coupling time constant for AC loss was 214 ms and 71.52ms before and after the cycling load, respectively. The test results of the sample are compared with the strand performance and parameter model analysis.     

The Influence of Magnetic Permeability on the Configuration of magnetic Field in Helimak Device

The Helimak of USA is a plasma physics experimental device designed and built by CASIPP.Its configuration of magnetic field is of very importance during the operation of this device.In this paper,the influence of magnetic permeability on configuration of magnetic field will be discussed due to the effect of weld metal in the vacuum vessel of Helimak,and some conclusion is useful for some engineering designs of the fusion experimental device.