带铁芯托卡马克装置的等离子体平衡数值解法

本文提出一种计算铁芯变压器托卡马克装置中等离子体平衡的数值方法。将铁芯对等离子体平衡的影响等效地看作外部线圈电流的作用,这样问题就转化为求解空芯变压器装置的等离子体平衡问题。这一方法的另一特点是计算区域减至最小。     

J-TEXT铁芯模型欧姆放电数值模拟

本文采用有限元软件分析了J-TEXT的完整铁芯模型、等离子体电流丝模型和简化中心螺线管模型的磁场特征,确定了简化中心螺线管的几何参数与电流,之后把有限长度中心通电螺线管参数加到托卡马克模拟程序TSC模型中,模拟J-TEXT的欧姆放电过程,获得了欧姆放电电流、电子温度、等离子体密度、等离子体电流,磁轴位置等参数。模拟结果与实验结果数据相符,为具有铁芯结构的托卡马克放电模拟提供了有效手段。     

HL—1装置等离子体位置反馈控制

本文简述了用位移做反馈控制信号,用非线性二位调节器组合前馈环节,控制厚钢壳(厚度d=5cm)外的垂直场和水平场线圈电流,在HL-1装置上实现了等离子体位置反馈控制的情况。当铁芯不饱和时,在水平和垂直两个方向上均可控制等离子体位置在±2mm之内。     

HL－1M装置等离子体的平衡和控制

ＨＬ－１Ｍ是ＨＬ－１的改进装置，去掉铜壳后，对极向场线圈和电源都做了必要的修改。此外，还增加了四个快垂直场线圈，并采用可控环流四象限晶闸管交流器供电。对装置调试和运行结果表明．反馈控制系统能很好地维持等离子体平衡。放电一直持续到铁芯变压器的伏秒数用完为止，最长达１０４０ｍｓ。在多数放电的平顶段，等离子体位置都被控制在±４ｍｍ之内．     

HT－7托卡马克中等离子体平衡研究

本文解决了二维轴对称近似下带铁芯的托卡马克中等离子体平衡问题，计算了ＨＴ－７托卡马克中的等离子体平衡位形以及极向场系统的非线性电感和垂直场系数。最后应用Ｋｉｒｃｈｈｏｆｆ方程组和平衡垂直场公式得到了一组等离子体、加热场和垂直场线圈的电流波形的自洽曲线。     

HT—7托卡马克中等离子体平衡研究

本文解决了二维轴对称近似下带铁芯的托卡马克中等离子体平衡问题，计算了ＨＴ－７托卡马克中的等离子体平衡位形以及极向场系统的非线性电感和垂直场系数。最后应用Ｋｉｒｃｈｈｏｆｆ方程组和平衡垂直场公式得到了一组等离子体，加热场和垂地直场线圈的电流波形的自洽曲线。     

HT-6A托卡马克平衡系统的实验

本文叙述了HT-6A托卡马克平衡系统及第一期平衡实验结果.讨论了HT-6A上铜壳对平衡的贡献;观察到改变垂直场形态因子n而产生的水平位移及垂直位移不稳定现象;介绍了正常放电时的平衡实验,观察到等离子体位移与MHD扰动是紧密相连的;用沙弗拉诺夫薄壳理论计算了对多大的等离子体电流应施加多大的垂直场,结果与实验完全符合。     

强磁场下ITER垂直稳定性线圈的电磁性能研究

垂直稳定性线圈是ITER托卡马克装置中用以维持等离子体垂直稳定性的核心部件,然而该线圈处于强磁环境下,一旦线圈励磁运行以后,线圈电流与外部背景场交互作用激发的电磁载荷将会对线圈产生强烈的电磁冲击.为了分析稳态和瞬态电磁载荷对线圈结构的影响,首先采用电流丝等效模型并基于椭圆积分计算了背景场线圈和等离子体电流的磁场,以及极端运行状态下背景场所诱发的电磁力.在电磁计算的基础上,创建循环对称磁-结构耦合分析模型并采用间接耦合法,将电磁力密度以载荷边界条件插值到结构分析模型,计算评估线圈在稳态电磁载荷下的力学性能.此外,针对脉冲电流引起的电磁疲劳,采用ASME主应力方向恒定的疲劳设计规范,结合Goodman修正法并以无限次循环条件下材料应力强度为评定标准,对线圈各组件的应力进行了评定,结果表明线圈各组件均有足够的安全裕度.该分析方法可为托卡马克其它磁体线圈的电磁性能评估提供参考.     

正弦（余弦）线圈探测等离子体位移方法的改进

用正弦(余弦)线圈与相应鞍形线圈感应信号的相加积分,来得到等离子体电流重心位移,是中小型托卡马克装置常用的方法,对了解与控制等离子体的平衡稳定,具有重要意义。但是在实际上由于中小装置放电时间较短,对等离子体电流及电流重心位移一般不加完善的控制,它们以及外加平衡控制场在放电期间都可以发生明显改变,从而在真空室壁中引     

HL-2A装置上一种测量等离子体位移的新方法

描述了用非对称结构的拾取线圈测量托卡马克装置等离子体位移和极向场不对称因子的方法,介绍了HL-2A装置拾取线圈的布置和位移测量的实验结果。并把用此方法测量的等离子体位移与用其他诊断方法测量的结果进行了比较。     

HL—1装置外垂直场代替内垂直场的改进

利用缝隙系数将钢壳内外各种电流源在壳内产生的磁场分成两部分,一部分按无壳处理,另一部分按无洞无缝的铜壶处理,因而各部分垂直场的解析计算结果与实验值符合很好,并能很好地解释HL-1装置平衡放电长达1S和外加垂直场很小的根本原因。经在装置上关闭内垂直场试验,结果表明,虽然有厚钢壳存在,外垂直场完全可以代替内垂直场。与以前相比,明显地改善了等离子体位置的平衡控制。     

非圆截面托卡马克轴对称模的反馈稳定

通过直接解真空区扰动磁面的边值问题,本文解析地研究了非闭合导壳对托卡马克中轴对称MHD模的反馈稳定性。我们取等离子体截面为椭圆,反馈系统由导壳和主动反馈线圈构成。结果表明,两块放在等离子体上下的导体块有很强的稳定作用;电阻壳可用以抑制高频模式,主动反馈线圈可用以稳定低频模式。 关键词：     

Comparative measurements of plasma position using coils,hall probes,and bolometers on CASTOR tokamak

Plasma position on CASTOR tokamak is measured by several systems based on different experimental methods. Vertical and horizontal plasma displacements are deduced from data of 4 Mirnov coils spaced poloidaly by 45°. Output of the Mirnov coils is routinely used as an input for automatic feed-back control of plasma position on CASTOR. Independently, we used an array of 16 Hall sensors, which measure the required magnetic field directly. Additional information on plasma position is obtained from two arrays of bolometers that measure horizontal and vertical profile of plasma radiation. Principle design of the all used diagnostics is given. Comparison of horizontal and vertical displacements deduced using various experimental methods is presented.     

HL-1装置的磁场测量

本文叙述了HL-1装置环向场线圈、内外垂直场线圈,欧姆变压器初级绕组和偏磁绕组的磁场测量方法和结果,初步讨论了带有切口的铜壳对磁场的影响。     

J-TEXT装置纵场电源系统及其调试

J-TEXT装置的纵场磁体是由十六个近似圆形的常规铜线圈串联而成。纵场电源系统需要为纵场磁体提供最大电流为160kA、平顶时间为500ms的准梯形电流波形,以在等离子体中心产生最大为3T的磁场。基于原TEXT-U纵场电源的电路结构,重新设计和改造了电源的控制系统和保护系统。目前,纵场电源系统已经通过了测试,在J-TEXT装置首轮放电运行中,该系统可输出92.5kA的平顶电流,在等离子体中心产生了约1.74T的磁场。     

Tokamak position control

A set of sensing coils to measure plasma position is described. The possibility of placing these coils outside a vacuum vessel (as a resistive shell) is considered by analyzing a feedback system for controlling otherwise unstable axisymmetric motion. A simple model was used to study the axisymmetric stability of a noncircular plasma surrounded by a conducting vacuum vessel and a feedback control system. Suitable choice of the various constants allowed a study of either horizontally or vertically unstable motion, either with or without an iron core and with various configurations for the vacuum vessel. Analytic expressions for the stability limits are derived, together with the specific response to a requested step displacement, giving the overshoot, steady-state error, decay times, and maximum power supply voltage. By suitably choosing an effective decay index both vertical and horizontal motion were studied. The results are applied to TEXT Upgrade (horizontal elongated, with iron core, horizontal unstable) using an effective decay index of -1     

A Magnet Field System for a High Density Tokamak Reactor

A design for a magnet system for a high density high field tokamak reactor is described. In this design stress in the trunk of the toroidal field structure is significantly reduced by elimination of the central ohmic heating transformer. In addition all superconducting coils are operated in the steady state and pulsed fields are generated only by copper coils.     

Study of the distributed <Emphasis Type="Italic">H</Emphasis>-parameter of an anisotropic optical fiber in a multi-layer coil of a fiberoptic gyroscope

An investigation has been performed on the distributed H-parameter in an anisotropic optical fiber with an elliptical strained shell in a multilayer coil of a fiberoptic gyroscope. Each fiber length is ~50 m and there are five layers. Studies have been carried out using three variants of coils. In the first variant, the layers were permeated by epoxy; in the second coil, the layers were permeated with silicon-based material; and, in the third variant, the coils were wound up without impregnation (using dry winding). The different influence of compressive mechanical stresses on the distributed H-parameter of the studied fiber has been observed depending on the variant of coil impregnation.     

Automatic system for dynamic control of resonance in high power and high Q ultrasonic transducers

This paper describes the fundamentals, design criteria and electronic structure of a new frequency control system to keep permanently at resonance high Q ultrasonic transducers whose mechanical resonance band may vary within wide limits under normal operating conditions. The procedure developed is based on keeping constant at its zero value the phase of the motional admittance of the transducer by automatically and instantaneously adjusting the frequency of the driving signal provided by a voltage controlled oscillator. The characteristics of this system, especially the fact that the transducer is not an integral part of the feed-back loop of the oscillatory circuit and the frequency tracking mechanism does not depend directly on the magnitude of the motional variables of the transducer, offer some advantages in construction and performance with respect to the conventional motional positive feed-back systems.