支持多种温度传感器的多通道低温测量系统的设计

中性束注入(neutral beam injector, NBI)系统的低温泵上必须设置一组温度测量点以监控其工作状态;为满足NBI温度测量需求,设计了一种支持多种温度传感器的多通道低温测量系统;系统采用24位Σ-Δ模数转换(analog-to-digital converter, ADC)芯片AD7193执行模数转换,采用控制器STM32F103ZET6控制设定恒流源、切换测量通道、ADC、以太网通信、串口通信、温度数据处理以及其他控制电路;该温度测量电路的设计可以用于由恒流源驱动的四线制低温温度测量领域。     

Control System of Neutral Beam Injection on HT-7

Neutral Beam Injection control system (NBICS) is constructed to measure the plasma current, Magnet current, vacuum pressure, cryopump temperature, control water cooling, filament voltage, and power supply， etc. The NBICS, consisting mainly of a Programmable Logic Controller (PLC) subsystem, data acquisition and processing subsystem and cryopump and vacuum pressure monitoring subsystem, has successfully been used on a NBI device. In this article, the design of NBICS on HT-7 is discussed and each subsystem is described in particular.In addition, some experimental results are reported which are very important data for further research related to the HT-7 tokamak.     

中性束注入器Tank充气特性对离子源放电的影响

利用对PV-10型压电阀定标实验,研究了中性束注入器Tank内补充气体的参数对离子源放电弧电流的影响,对比压电阀脉冲电源的脉宽和幅值,显示后者对Tank内补充气体量具有更显著的线性关系.据此进行的中性束注入器离子源放电实验结果表明,采用压电阀定标值计算获得的参数,可以稳定重复地获得最大放电脉宽达到400 ms的等离子体弧电流,为下一步向托卡马克装置注入高能中性粒子束奠定了应用基础.     

Thermal analysis of EAST neutral beam injectors for long-pulse beam operation

Two sets of neutral beam injectors(NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with indepth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that(1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline,(2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and(3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.     

EAST-NBI用差分式低温冷凝泵的设计

为了维持EAST-NBI内的真空环境以满足中性束生成与传输过程对真空压力分布的要求,设计了EAST-NBI用差分式低温冷凝泵.本文概述了中性束注入加热的原理以及EAST-NBI真空系统的组成,详细阐述了EAST-NBI用差分式低温冷凝泵的结构设计,抽速和冷凝面积的确定,液氦系统和液氮系统热负荷的计算等关键问题.该差分式低温冷凝泵通过在EAST-NBI综合测试台上进行大量实验验证,完全满足EAST-NBI对真空系统的要求.     

HT-7诊断中性束装置真空远程监控系统设计

本文介绍了真空实时远程监控系统的设计要求,讨论了该系统的硬件设计、软件设计及其工作原理,给出了部分实验结果。系统成功地应用于实验并获得理想的实验结果,为诊断中性束稳态运行提供可靠保障。     

诊断中性束装置离子源起弧实验的多元非线性回归分析

通过调节影响诊断中性束离子源弧流的进气量、灯丝电流和弧压三个参量，进行了三组离子源起弧实验。建立了多元非线性回归模型，得到了三个参量对弧流的回归方程。回归分析表明，弧流对进气量和灯丝电流相当敏感，且有趋于饱和的特征，这与实验结果相吻合。在进气针阀开度492、灯丝总电流469A、弧压190V时重复起弧，均得到弧流170A以上、脉宽150ms的稳态放电，满足了诊断中性束流对弧流的要求。     

DNB束功率测量系统设计

设计了测量诊断中性束(DNB)束功率及束密度剖面的束功率测量方案,采用热电偶测量束线轰击功率测量靶板后靶面的温升信号,经热电偶信号调理器调制放大后,由数据采集卡采集到现场计算机中进行数据处理,以及功率大小和功率密度剖面分布的计算,计算值通过光纤链路传输到控制室终端计算机加以复现.实验证明,DNB束功率测量系统工作稳定可靠,实现了对束线轰击靶板后靶面温升的实时测量,和对束线功率大小及功率密度剖面的良好复现.     

关于超光速的一种准确表述

从两个相对运动坐标系的速度变换关系,说明了一切实物粒子与场超光速的不可实现性,揭示了爱因斯坦狭义相对论的一个隐含内容。然后从色散介质中相速度与群速度的关系,讨论了相速度和群速度超光速的可能性。从而给出了关于超光速问题的一个较为准确的表述。     

EAST中性束注入器束中性化区气流模拟分析

中性束注入(Neutral Beam Injection)加热是磁约束核聚变装置上主要的辅助加热手段。强流离子束中性化是中性束注入的关键步骤,它直接决定了中性束的注入功率,进而影响对等离子体的加热效果。本文分析了EAST中性束注入器束中性化区的气流特性,发展了基于直接模拟蒙特卡洛(DSMC)方法的气流模拟程序,并用于EAST中性束注入器束中性化区的模拟分析和优化设计。