�п���˵����������ѵĻ����Ԥ���о�

HL-2A和HL-1M装置采用了激光吹气注入高Z杂质来缓减大破裂中的等离子体电流衰竭,并给出了初步实验结果。在HL-2A装置上建立了利用MHD扰动的参量预报放电破裂先兆的报警系统,研制了MHD实时检测与处理系统,实现了放电破裂先兆的预报、快速触发激光吹气、形成阻性高辐射等离子体、消耗热能和磁能,缓减大破裂。实验证明,这是一种使得大型聚变实验装置在放电破裂之前显著减少等离子体中热能和磁能,而且能安全终止放电的简单、快速和有效的途径。     

�п�����о�����Ŷ�����ĸ�����������ʧ�о�

Based on ORBIT code of a guiding center motion of single particle, the loss of energetic ions in different radial positions of tokamak plasma is studied by using test particle simulation method. The results show that the local magnetic perturbations can cause loss of many energetic ions near the central region of the plasma, but they have little effect on the ion loss near the plasma boundary, assuming that the local field is mainly located near a magnetic surface and its toroidal field is similar to the ripple field. These energetic ions are trapped ions, and the greater their pitch angle is, the easier they lose. In addition, the radial position of the local field that causes the maximum loss rate of energetic ions is usually offset from the initial radial position of these loss ions, and this shift is closely related to the energy of these ions. When the local field appears in certain locations, the ions of lower energy have some loss, but the ions higher energy does not lose.     

�п���˵������廷��ת���Բ����ģ��Ӱ��

采用回旋动理学方程推导得到了环向转动托卡马克等离子体中测地声模的色散关系,分析了环向转动对测地声模、低频模和声波分支的频率以及无碰撞阻尼率的影响.结果表明,测地声模的频率会随着环向转动马赫数而逐渐增大,而其无碰撞阻尼率则会随着环向转动马赫数而迅速减小.此外,低频模和声波分支的频率以及无碰撞阻尼率都会随着环向转动马赫数而逐渐减小,其中环向转动对声波分支的频率以及无碰撞阻尼率的影响非常小,基本上可以忽略.     

�п���˱�Ե�����д�״���ĸ�ճ������

基于Hasegawa-Wakatani湍流模型,数值模拟了托卡马克边缘等离子体中漂移波湍流和相关的反常粒子输运.从等离子体动量守恒方程出发导出了不采用常规的布辛涅斯克近似的带状流方程,论证了大振幅密度扰动和湍性粒子流对激发带状流的贡献可等效地对应于低阶负粘滞阻尼效果.数值模拟表明,大振幅密度扰动的非线性大大增强了带状流饱和振幅,从而有效抑制了湍性粒子输运.研究结果阐明了托卡马克边缘等离子体大振幅密度扰动的非线性对驱动等离子体旋转、动量输运和带状流的重要性.     

�п���˵���ƽ�������µ������廷��ת���Դ�״����Ӱ��

采用流体模型理论推导了等熵平衡条件下环向转动托卡马克等离子体中带状流的色散关系。从理论上分析了环向转动对测地声模、低频带状流和声波的频率、压力和密度扰动量的影响。结果表明,环向转动对低频带状流的频率没有影响,但会使测地声模的频率逐渐增大。此外,存在环向转动时,低频带状流会具有驻波形式的压力和密度扰动量,且测地声模和声波可以沿着极向传播。而且还发现,等熵平衡可以看成是等温平衡的一种特殊情况。     

����״̬�Գ����п�������¾�Ե�ӵ�����Ӱ��ʵ���о�

为了解不同氦气状态对超导托卡马克室温绝缘子电性能的影响,建造了室温绝缘子氦气状态下电性能测试平台.利用该平台,在静态氦气和氦气流速为0.65g·s?1状态下进行了室温绝缘子高电压-漏电流实验.实验结果表明,两种氦气状态下室温绝缘子均满足使用要求.     

�п����װ���дų�̽��궨ϵͳ

讨论了用于磁场测量的磁感应线圈的有效感应面积和积分器的积分时间这两个参数的精确标定,描述了两种标定系统的测量原理以及其相应的特点。     

SUNIST�����п���˵�������߽�ʶ���о�

利用电流丝模型对SUNIST球形托卡马克等离子体边界重构进行了模拟计算。结果表明,用电流丝模型能够比较好地对等离子体自由边界进行快速识别,与EFIT平衡计算的边界径向平均误差小于6mm。     

EAST�п����װ�ùؼ�����װ��Ŀ��Ʋ���

采用精密工程测量技术对EAST装置主机关键部件装配位置进行了装配过程检测，并建立了相应的测量控制网。通过利用合适的控制测量方案，使得EAST装置关键部件的装配位置精度达到了设计要求。     

托卡马克二维局部模的第三类气球理论

采用二维气球表象,在已有第一类和第二类气球理论的基础上,构造了第三类气球理论。与第一类气球理论相比,扩展了后者因受可解性条件限制的适用范围;与第二类气球理论相比,因容纳了“坏曲率”效应而获得具有更高增长率的解,故与采用初值数值模拟方法所得的结果更具可比性。本文以流体型离子温度梯度模为例,用第三类气球理论求解了二维本征值问题,计算了所选剖面参数下的本征频率和模式结构,并与前两种理论所得的结果进行了比较和讨论;也讨论了该理论对实现托卡马克高约束的意义。     

Hidden symmetries in two dimensional field theory

The bosonization process elegantly shows the equivalence of massless scalar and fermion fields in two space-time dimensions. However, with multiple fermions the technique often obscures global symmetries. Witten’s non-Abelian bosonization makes these symmetries explicit, but at the expense of a somewhat complicated bosonic action. Frenkel and Kac have presented an intricate mathematical formalism relating the various approaches. Here, I reduce these arguments to the simplest case of a single massless scalar field. In particular, using only elementary quantum field theory concepts, I expose a hidden SU (2) × SU (2) chiral symmetry in this trivial theory. I then discuss in what sense this field should be interpreted as a Goldstone boson.     

Role of flow shear in the ballooning stability of tokamak transport barriers

A tokamak's confinement time is greatly increased by a transport barrier (TB), a region having a high pressure gradient and usually also a strongly sheared plasma flow. The pressure gradient in a TB can be limited by ideal magnetohydrodynamic instabilities with a high toroidal mode number n ("ballooning modes"). Previous studies in the limit n--> infinity showed that arbitrarily small (but nonzero) flow shears have a large stabilizing influence. In contrast, the more realistic finite n ballooning modes studied here are found to be insensitive to sub-Alfvénic flow shears, provided the magnetic shear s approximately 1 (typical for TBs near the plasma's edge). However, for the lower magnetic shears that are associated with internal transport barriers, significantly lower flow shears will influence ballooning mode stability, and flow shear should be retained in the analysis of their stability.     

Duality symmetry group of two dimensional heterotic string theory

The equations of motion of the massless sector of the two dimensional string theory, obtained by compactifying the heterotic string theory on an eight dimensional torus, is known to have an affine o(8,24) symmetry algebra generating an O(8,24) loop group. In this paper we study how various known discrete S- and T- duality symmetries of the theory are embedded in this loop group. This allows us to identify the generators of the discrete duality symmetry group of the two dimensional string theory.