Optimization of Helical Magnetic Configuration

为了在本项目下开展卓有成效的国际合作，我们确定了两个子项目：(1)开发利用ECCD方法在螺旋轴结构中控制电流的ECH和ECE分析工具；(2)开发抑制螺旋轴结构中等离子体波动的等离子体波动数据库。在子项目(1)中，我们与CIEMAT合作开发了射线追踪代码（TRECE），用于分析ECH微波在三维磁场构型下的ECH功率吸收。利用该程序和本项目部分资助的ECE辐射计，对Heliotron J的热输运进行了研究。在子项目(2)中，对代码进行了改进，以分析Heliotron J中的ECCD实验。在子项目(2)中，对Heliotron J、TJ-II和U-3M三种不同配置的设备进行了协作实验，主要针对边缘等离子体湍流进行了实验，并采用了通用的诊断方法。这一合作发现了边缘等离子体湍流特性的一些异同。指出了Levy指数对具有间歇性质的边缘等离子体湍流进行分类的有效性，这是边缘等离子体湍流的共同特征之一。已经提出了用于波动研究的新诊断方法和/或分析技术，并对其中一些方法进行了初步研究。

In order to make fruitful international collaborations under this project, we set two sub-projects: (1) Development of tools for ECH and ECE analyses for current control by using the ECCD method in helical-axis configurations, (2) Development of plasma fluctuation database for suppression of plasma fluctuation in helical-axis configurations.Under the sub-project (1), we have developed a ray-tracing code (TRECE) under the collaboration with CIEMAT to analyze ECH power absorption of ECH microwaves in three-dimensional magnetic fields configuration. By using this code and ECE radiometer equipped through a partial support from this project, the study of heat transport in Heliotron J has been progressed. The code has been improved to analyze ECCD experiments in Heliotron J.Under the sub-project (2), Collaborative experiments among three devices with different configurations (Heliotron J, TJ-II and U-3M) have been performed mainly focused on the edge plasma turbulence, where a common diagnostic method has been used. This collaboration has found out some similarities and differences in the characteristics of edge plasma turbulence. It is also pointed out the effectiveness of Levy Index to classify the edge plasma turbulence with intermittent nature, which is one of common features in the edge plasma turbulence. New diagnostic methods and/or analyzing technique for the fluctuation study have been proposed and pilot studies with some of such methods have been performed.