非軸対称トーラスプラズマにおける三次元MHD平衡・安定性と高エネルギー粒子

在托卡马克和仿星器等环面等离子体中，研究等离子体的MHD特性与高能粒子（如α粒子）之间的关系对于实现热核聚变反应堆是不可避免的，也是重要的。本文对非轴对称环面等离子体中高能粒子与三维MHD平衡稳定性的关系进行了理论和数值分析；1)采用基于仿星器近似的全局MHD稳定码，研究了Alfvan连续谱间隙中存在的离散特征模。研究发现，有限等离子体β引起的旋转变换轮廓的改变会改变TAE模的模结构和频率。高能粒子对TAE模式的动力学效应目前正在进行微扰研究。2)基于WKB近似的局部分析和基于三维理想MHD稳定性的全局分析，对螺旋系统特有的气胀模式进行了更多的CAS3D分析。通过对局部分析和全局分析的详细比较，验证了局部分析的有效性，其中指出了近似的有效性存在问题。为了估计动力效应对理想气胀模式的影响，对动力学气胀模式方程进行了局部分析。我们发现有限拉莫尔半径效应（FLR）对短波模稳定有效，而可压缩性对长波模稳定有效。3)已经开始开发蒙特卡罗代码，以从粒子的角度估计作为最终目标的动力学效应。第一步，我们正在研究螺旋系统中等离子体的新古典输运。虽然很难定量地论证这些结果，但我们定性地证实了先前研究中证明的由颠簸场分量和径向电场抑制新古典输运的结果。4)在脉动托卡马克分析中，采用Biot-Savart编码KMAG和三维MHD平衡编码VMEC，考虑环面线圈的离散性，得到了自由边界MHD平衡。阐明了环形场纹波的有限依赖关系及其对高能粒子纹波损耗的影响。少

In torus plasmas such as tokamaks and stellarators, investigation of the relation between MHD properties of the plasma and high energy particles like alpha particles is inevitable and important to realize a thermo-nuclear fusion reactor. In this study, following theoretical and numerical analyses are performed concerning the correlation between three-dimensional MHD equilibrium/stability and high energy particles in non-axisymmetric torus plasmas;1) Discrete eigenmodes existing in the spectral gap of Alfvan continuum are studied by using a global MHD stability code based on the stellarator approximation. It is found that the mode structure and frequency of the TAE modes are changed by the change of the rotational transform profile due to the finite plasma beta. The kinetic effect of high energy particles on the TAE mode is being studied perturbatively now.2) Both the local analysis based on the WKB approximation and the global analysis by using a three-dimensional ideal MHD stability c … More ode CAS3D are performed for the ballooning mode specific to the helical system. From the detailed comparison between the local and global analysis, the availability of the local analysis, in which the validity of the approximation is pointed out to be questionable, is verified. In order to estimate how the kinetic effect can change the ideal ballooning mode, local analyses solving the kinetic ballooning mode equations are done. We found that the finite Larmor radius (FLR) effect stabilizes short wave length modes and the compressibility is effective to stabilize long wave length modes.3) Development of a Monte-Carlo code has been started to estimate kinetic effects from the view point of particles as a final goal. At the first step, the neoclassical transport is being investigated for a plasma in a helical system. Heliotron J. Though it is difficult to argue the results quantitatively, suppression of the neoclassical transport due to the bumpy field component and the radial electric field, which is demonstrated in the previous studies, is verified qualitatively.4) In the analysis of a rippled tokamak, free-boundary MHD equilibria are obtained by considering discreteness of toroidal coils using a Biot-Savart code KMAG and a three-dimensional MHD equilibrium code VMEC. Finite beta dependence of the toroidal field ripple and its effect on the ripple loss of high energy particles are clarified. Less