Spectroscopic Measurements of Impurity Spectra on the EAST Tokamak

Ultraviolet (UV) and visible impurity spectra (200～750 nm) are commonly used to study plasma and wall interactions in magnetic fusion plasmas. Two optical multi-channel analysis (OMA) systems have been installed for the UV-visible spectrum measurement on EAST. These two OMA systems are both equipped with the Czerny-Turner (C-T) type spectrometer. The upper vacuum vessel and inner divertor baffle can be viewed simultaneously through two optical lenses. The OMA1 system is mainly used for multi-impurity lines radiation measurement. A 280 nm wavelength range can be covered by a 300 mm focal length spectrometer equipped with a 300 grooves/mm grating. The Dα/Hα line shapes can be resolved by the OMA2 system. The focal length is 750 mm. The spectral resolution can be up to 0.01 nm using a 1800 grooves/mm grating. The impurity behaviour and hydrogen ratio evolution after boroniztion, lithium coating, and siliconization are compared. Lithium coating has shown beneficial effects on the reduction of edge recycling and low Z impurity (C,O) influx. The impurity expelling effect of the divertor configuration is also briefly discussed through multi-channels observation of OMA1 system.     

贝叶斯反卷积在EAST电荷交换复合光谱分析中的应用

电荷交换复合光谱(Charge e Xchange Recombination Spectroscopy,CXRS)诊断是核聚变装置上测量等离子体离子温度和旋转速度的常规诊断之一。然而在实验中,诊断光通过光谱仪后,由于仪器函数的卷积效应,会使测量到的光谱出现明显展宽,影响数据处理的精度,所以需要对实验测量到的光谱进行反卷积处理。本文采用的反卷积方法是基于贝叶斯条件概率公式推导得出,并结合标准灯获取的仪器函数来进行反卷积,分别从仿真和实验两个方面验证了该方法的可靠性。结果表明将贝叶斯反卷积运用到先进实验超导托卡马克(Experimental Advanced Superconducting Tokamak,EAST)电荷交换复合光谱分析中,能有效提高实验测量精度。结合快速极紫外谱仪(Extreme ultraviolet,EUV),对EAST实验中经过贝叶斯反卷积后测量到的光谱进行了杂质谱线识别工作,进一步提高了精度。     

Impurity Emission Behavior in the Soft X-Ray and Extreme Ultraviolet Range on EAST

Spectroscopy in the soft X-ray and extreme ultraviolet(XEUV) region is very important in magnetic fusion research.Recently,two flat-field spectrometers that utilize a varied line spacing grating to image the spectra of 1-13 nm and 5-50 nm were installed on EAST for core impurity emission monitoring and impurity transport study.The instruments were proven to be capable of observing spectral lines from low-Z impurities(Li,C,O,N,Ar,etc.) and highly ionized medium- and high-Z impurities(Fe,Cr,Ni,Cu,Mo,etc.).For example,spectra in the wavelength intervals of 1-2 nm and 5-13 nm contained strong metal lines,especially molybdenum lines during H-mode phases.Argon and nitrogen lines were also observed,which were injected for diagnostic purposes.Impurity lines were identified and compared to measurements on other magnetic fusion research devices.Detailed measurements of radial emission profiles from various impurity line emissions were also presented.     

EAST运动斯塔克效应诊断的信号处理分析系统设计

运动斯塔克效应诊断利用光弹调制偏振测量技术可将偏振角的空间方向的测量转化为对二倍频信号强度比值的求取。为精准、快速地获取二倍频信号幅值,设计了基于FPGA的运动斯塔克效应诊断数字频谱分析系统,系统采用高速ADC采集运动斯塔克效应信号后送入FPGA,以EP2AGX125型FPGA为核心进行快速傅里叶变换获得信号频谱,求取二倍频分量的幅值进而计算出偏振角。经仿真与实验测试,该系统的测量精度好于5%,工作周期小于10 ms,满足MSE诊断信号处理要求。     

托卡马克等离子体杂质密度的光谱法测量研究

本文介绍了基于托卡马克等离子体被动光谱诊断获得杂质密度的方法。通过被动光谱诊断测量获得杂质线辐射的空间多道弦积分强度分布,利用强度标定系数转换为绝对光亮度分布;通过测量弦与等离子体位形,将弦积分的强度分布反演变换为径向体发射率。根据线辐射强度激发截面求出对应电离态的离子密度,最后采用杂质输运程序模拟计算得出总密度分布。以东方超环(Experimental Advanced Superconducting Tokamak,EAST)托卡马克装置上软X射线-极紫外光谱(Soft X-ray and Extreme Ultraviolet Spectrometers,XEUV)诊断测量到的Mo XXIX-Mo XXXII为例,描叙了获得Mo杂质密度分布的过程,获得的总误差小于10%。     

Test of a High Throughput Detector on the X-ray Crystal Spectrometer of the EAST

An attempt was made to improve the spatio-temporal resolution of the tangen- tial X-ray crystal spectrometer (XCS) on the Experimental Advanced Superconducting Tokamak (EAST) by evaluating experimentally the applicability of a novel X-ray photon detection tech- nology for measuring the satellite spectra of Ar XVII with a high counting rate. High-resolution experimental data on the profiles of ion temperature and plasma rotation velocity facilitate the studies of the mechanisms underlining important physical phenomena, such as plasma heating, L-H transition and momentum transport. Based on silicon diode array and single-photon counting technology, a relatively small area (83.8×33.5 mm 2 ) two-dimensional detector was successfully in- stalled and tested in the recent EAST campaign. X-ray photon counting rate higher than 20 MHz was observed for the first time, and high quality satellite spectra were recorded for ion temperature and plasma rotation measurement, indicating that the new technology is suitable for the next-step high-resolution XCS on EAST, and the deployment of a detector array with a much larger X-ray sensing area is planned for better plasma coverage.     

EAST边界旋转诊断的光路分析

具有空间和时间分辨的边界旋转诊断(ERD)已在EAST装置上研制完成,经调试已投入EAST实验研究中。多道光纤的观测视线已进行位置标定,经过分析,每道光纤所能耦合的离子辐射通量可表述为解析形式的弦积分量。使用卤素气体标准灯对光谱仪进行了波长标定,并确定了仪器响应函数。ERD可提供边界离子温度和旋转速度,是研究C、O、Li、N、He、Ar等离子在可见光波段辐射的有效工具。通过对CIII谱线的分析,得到了边界离子温度和边界旋转速度的初步实验结果,环向ERD初步实验结果表明ERD测量边界杂质离子温度及旋转速度的可行性。     

Inversion techniques to obtain local rotation velocity and ion temperature profiles for the x-ray crystal spectrometer on EAST

Inversion techniques are conducted based on the tangential x-ray crystal spectroscopy(TXCS)geometry on EAST to obtain the local profiles of ion temperature(T_i) and toroidal rotation velocity(vt). Firstly, local emissivity profiles of the impurity argon are obtained using the asymmetrical Abel inversion.Then, the local vtand T_i profiles are calculated by considering the local emissivity profiles and the TXCS detailed geometry. In addition, how the changes in the v_t     

EAST辐射偏滤器运行模式下等离子体杂质浓度评估方法

通过在偏滤器区域充入适量氖气（Ne）或氩气（Ar）,东方超环（Experimental Advanced Super-conducting Tokamak,EAST）托卡马克装置实现了辐射偏滤器运行模式。在辐射偏滤器运行模式下,靶板热负荷显著降低,有效缓解了高能粒子流对偏滤器靶板的损伤。但是在偏滤器区域充入过量杂质气体时,杂质粒子会沿着磁力线进入主等离子体,影响主等离子体的约束性能,甚至导致等离子体破裂。因此,有必要研究偏滤器区域等离子体杂质浓度的估算方法,分析充入杂质气体时该区域杂质的定量变化,以此来评估充入的杂质气体对芯部等离子体约束性能的影响。本文针对不同的杂质种类,建立了不同的杂质浓度估算方法。对于钨杂质,通过极紫外光谱（Extreme Ultraviolet Spectroscopy,EUV）诊断系统测量偏滤器区域钨杂质的辐射强度,再根据碰撞-辐射模型对该区域的钨杂质浓度进行了估算。对于Ne杂质,则通过等离子体有效电荷数(Z_eff)的变化进行了Ne杂质浓度估算。基于估算结果,对辐射偏滤器条件下的芯部杂质行为进行了讨论。上述杂质浓度评估方法对开展辐射偏滤器...     

钢筋混凝土构件的尺寸效应研究进展及展望

为提高大尺寸钢筋混凝土构件设计的合理性,对各国钢筋混凝土构件的尺寸效应研究现状进行了综述与分析,并重点介绍了混凝土强度、钢筋混凝土梁和钢筋混凝土柱的尺寸效应试验研究成果;在归纳总结的基础上,对钢筋混凝土构件尺寸效应研究的发展进行了展望,建议了进行涵盖大尺寸混凝土构件破坏试验的尺寸效应研究方案.