Semi-analytic Modeling of Tokamak Particle Transport

1.IntroductionAstudyonparticleconfinementandtransportisoneofthemostfundamentalandimportanttopicsofthemagneticconfinementphysics.Experimentsshowthattheparticleconfinemelltnotonlyaffectsdirectlytheplasmaenergystorageandtheglobalenergycqnfinementtime,butalsoiscloselyrelatedwiththeconfinementmodethroughdensityprofileeffects.Asexamples,animProvedOhmicconfine-mentmode(IOC)isrealizedbypeakingtheden-sityprofile[l1,anotherimprovedconfinementmodecalledthesupershotfoundintheTFTRdeviceisre-latedwithth…     

全自动六工位混凝土塌落度测量仪的研发

针对人工测量时间长、误差大的问题,研发了一种全自动六工位混凝土塌落度测量仪,该仪器具备自动多次下料、多次插捣、提桶、拉绳激光测量、卸料以及自动显示塌落度结果等功能,且操作简单方便,测量时间短,很好地满足了建筑施工现场测量要求。     

Impact of resonant magnetic perturbation on blob motion and structure using a gas puff imaging diagnostic on the HL-2A tokamak

The impact of resonant magnetic perturbation(RMP) on blob motion and structure in the SOL of the HL-2A tokamak is studied using a gas puff imaging diagnostic. Ellipse fitting is applied to study the structure and motion of blobs quantitatively. The radial locations, amplitudes and scale sizes of blobs are obtained based on the fitted ellipse. Furthermore, based on the measurement of blob location, the radial and poloidal velocities of blobs are calculated. With the application of RMP, the edge p...     

Dynamics of Secondary Large-Scale Structures in ETG Turbulence Simulations

The dynamics of secondary large-scale structures in electron-temperature-gradient （ETG） turbulence is investigated based on gyrofluid simulations in sheared slab geometry. It is found that structural bifurcation to zonal flow dominated or streamer-like states depends on the spectral anisotropy of turbulent ETG fluctuation, which is governed by the magnetic shear. The turbulent electron transport is suppressed by enhanced zonal flows. However, it is still low even if the streamer is formed in ETG turbulence with strong shears. It is shown that the low transport may be related to the secondary excitation of poloidal long-wavelength mode due to the beat wave of the most unstable components or a modulation instability. This large-scale structure with a low frequency and a long wavelength may saturate, or at least contribute to the saturation of ETG fluctuations through a poloidal mode coupling. The result suggests a low fluctuation level in ETG turbulence.     

托卡马克等离子体粒子输运方程的半解析研究

粒子约束和输运特性的研究是磁约束聚变物理研究最基本的和最重要的课题之一。大量实验表明粒子约束好坏不仅直接影响等离子体储能,而直接与总体能量约束时间有关,而且粒子密度的剖面分布与约束模式有内在的联系。这里的粒子除工作粒子(一般指氢、氘)外,也包括杂质。文献[1]对杂质输运方程的一般特性进行了系统研究,本文将该文所述方法     

杂散光对分光光度计测量结果的影响

可见分光光度计及紫外一可见分光光度计(UV-VIS)在制药行业中普遍使用,影响该仪器测量误差的因素很多,其中杂散光是主要来源之一。现就杂散光这一项目对仪器测量结果准确性的影响予以说明。     

Preparation of a beam emission spectroscopy diagnostic based on a Lyman-alpha line to diagnose core and edge-plasma density fluctuation on the HL-2A tokamak

In this article, the design of a Lyman-alpha-based beam emission spectroscopy(LAB) diagnostic on the HL-2A tokamak has been proposed for the first time. The purpose of this novel diagnostic is to measure density fluctuations of tokamak plasma. The light-collection system of LAB, which consists of the first mirror and two groups of coaxial double-mirror telescopes, can realize a twosegmented viewing field of ρ = 0–0.2 and ρ = 0.75–1, which is optimized to measure plasma density fluctuation, not o...     

Magnetic-island-induced ion temperature gradient mode: Landau damping,equilibrium magnetic shear and pressure flattening effects

Characteristics of the magnetic-island-induced ion temperature gradient (MITG) mode are studied through gyrofluid simulations in the slab geometry,focusing on the effects of Landau damping,equilibrium magnetic shear (EMS),and pressure flattening.It is shown that the magnetic island may enhance the Landau damping of the system by inducing the radial magnetic field.Moreover,the radial eigenmode numbers of most MITG poloidal harmonics are increased by the magnetic island so that the MITG mode is destabilized in the low EMS regime.In addition,the pressure profile flattening effect inside a magnetic island hardly affects the growth of the whole MITG mode,while it has different local effects near the O-point and the X-point regions.In comparison with the non-zero-order perturbations,only the quasi-linear flattening effect due to the zonal pressure is the effective component to impact the growth rate of the mode.     

A brief review: experimental investigation of zonal flows and geodesic acoustic modes in fusion plasmas

Zonal flows self-generated by turbulence play an important role in regulating turbulence, reducing transport level, and thus improve plasma confinement in fusion plasmas. The zonal flows and geodesic acoustic modes have been identified in various devices. The related issues, such as the poloidal and toroidal symmetries, coupling to turbulence, effects on turbulence and transport, nonlinear energy transfer between turbulence and zonal flows, dependence of the plasma parameters, roles in the confinement regime transitions etc are overviewed briefly in this paper. The interaction between zonal flows and magnetic islands is emphasized.     

无碰撞捕获离子温度梯度不稳定性

保留捕获离子平行可压缩性,研究了本征频率接近离子弹跳频率的静电无碰撞捕获离子温度梯度不稳定性。结果表明不稳定性的本征模存在于整个参数b范围。在相对短波长范围,只存在一个局部不稳定的平板模分支。在相对长波长极限下,发现了非局部的不稳定的环形分支和平板分支。对这些不稳定模的本征频率,传播特性和本征模结构也进行了详细地解析和数值研究,解析分析和数值计算结果符合得很好。