Investigation of impurity transport using supersonic molecular beam injected neon in HL-2A ECRH plasma

In this paper, we describe the behavior of impurity transport in the HL-2A electron cyclotron resonance heating （ECRH） L-mode plasma. The neon as a trace impurity is injected by the supersonic molecular beam injection （SMBI） technique, which is used for the first time to study the impurity transport in HL-2A. The progression of neon ions is monitored by the soft X-ray camera and bolometer arrays with good temporal and spatial resolutions. The convection and diffusion process of the neon ions are investigated with the one-dimensional impurity transport code STRAHL. The results show that the diffusion coefficient D of neon ions is a factor of four larger than the neoclassical value in the central region. The value of D is larger in the outer region of the plasma （ρ 〉 0.6） than in the central region of the plasma （ρ 〈 0.6）. The convective velocity directs inwards with a value of ～-1.0 m/s in the Ohmic discharge, but it reverses to direct outwards with a value of ～ 8.0 m/s in the outer region of the plasma when ECRH is applied. The result indicates that the impurity transport is strongly enhanced with ECRH.     

新题征展(112)

A 题组新编 　　1.(邓晓锋)过抛物线x2=2py的焦点F的弦AB的端点A,B的切线分别为AT,BT,求证:……     

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在HL-2A的实验中,我们采用了一种像素法二维层析成像分析技术对软X射线进行反演成像。该方法可对等离子体截面软X射线分布提供详细及可视化的研究方法。该二维层析反演方法已经在HL-2A上得到了成功应用,重建了杂质注入过程和双锯齿破裂过程。     

HL-2M 装置软 X 射线阵列系统前置放大器设计

系统地介绍了 HL-2M 装置上软 X 射线阵列系统的工程概念设计、组成部分、关键工艺和技术研制 等。根据 HL-2M 装置的特点(如高温烘烤,真空室空间不足等),在该系统前置放大器设计中采用了很低的失调电 压和超低的偏置电流的高速宽带放大电路来降低暗电流和噪声,使得系统适用于较长距离传输的光电前置放大场 合,从而首次实现了前置放大器外置于真空室的安装布局。该放大器将大大增强整套软 X 射线阵列系统在高温烘 烤条件下的可靠性。      

新题征展(121)

A 题组新编 1.(胡寅年)(1)以一个正方体的顶点为顶点的四面体共有 A.70个B.64个C.58个D.52个 (2)以一个正方体的顶点为顶点的正四面体共有 A.2个B.8个C.16个D.24个 (3)以一个正方体的顶点为顶点的正三棱锥共有 A.8个B.10个C.16个D.24个 (4)以一个正方体的顶点为顶点的四个面都是直角三角形的三棱锥共有 A.12个B.24个C.36个D.48个 2.(胡寅年)(1)设f(x)是定义在(-∞,+∞)上的可导函数,且满足f'x+f(x)>0,对任意正实数a,下面不等式恒成立的是     

HL-1M弹丸加料等离子体中的蛇形振荡

根据PIN光二极管阵列探测器所探测到的1～10keV能量范围的软X射线辐射扰动．研究了HL-1M装置等离子体中在多发弹丸注入条件下产生的蛇形振荡不稳定性特性,对其机制进行了仔细讨论。实验表明,在中等密度欧姆放电中。高速弹丸注人能直接在等离子体芯部激发出蛇形振荡。对于较高密度的放电,在弹丸加料等离子体的后续演变中经常观测到锯齿稳定化结束时诱发出的准稳态大幅度蛇形振荡。     

椭圆截面的Abel逆变换方法

介绍了等离子体椭圆截面的Abel逆变换方法,并和圆截面的Abel逆变换方法进行了比较。给定一个探测阵列对一个辐射源函数的测量结果,分别用Barr方法、等值同心圆方法和幂级数方法进行了椭圆逆变换,结果表明该方法的可靠性可应用于实验数据处理中。     

Observation of Fishbone-Like Instabilities Excited by Energetic Electrons on the HL-2A Tokamak

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新题征展(108)

A 题组新编 　　1.(翁华木)(1)将边长为为2的正方形ABCD沿对角线BD折叠起来,使顶点A在底面BCD上的射影恰好是△BCD的外心O,如图1所示,则AO=_____;又若P是侧面ABD上的一动点,点P到平面BCD的距离与到点A的距离相等,则动点P的轨迹是_____.(用文字描述轨迹的形状,下同)……