Comparative Study of Helical Magnetic Configurations Relevant to Confinement and Steady-State Experiments

为了实现未来的聚变反应堆，螺旋等离子体约束系统被认为是一个有影响力的托卡马克系统的替代方案。日本国立核聚变科学研究所的大型螺旋装置（LHD）在螺旋系统中处于领先地位。在德国，一种同样大小的螺旋装置正在建造中，但具有不同的磁性结构。相互合作是非常重要的。本研究的主要目的是建立日本、德国和西班牙之间的输运数据库，以阐明螺旋等离子体的约束机制，并促进国际能源署仿星器实施协议下的国际合作实验。在这项为期三年的科研项目中，我们进行了以下有益的研究合作：(1)项目规划与研究考察：为推进LHD国际互励实验（LIME）项目，研究螺旋等离子体的高性能和稳态维持，多名研究人员访问欧洲，参加国际能源署（IEA）国际执行定星器会议。(2)个人科研合作交流：为展示本项目资助研究成果，部分科学家出国参加国际学术会议，与国外科学家进行交流讨论。特别讨论了等离子体约束、传输代码开发和未来合作计划方面的差异。(3)约束、诊断和反应堆相关的国外科学家邀请：在本研究框架内，邀请了德国、瑞士、美国、俄罗斯等多位国外科学家，开展了等离子体约束、诊断和反应堆设计等多种合作研究，促进了LIME项目的发展。这些研究合作在国际能源署仿星器执行协议下的国际执行委员会中得到了高度评价。

In order to realize future fusion reactors, helical plasma confinement system is considered as an influential alternative to the Tokamak systems. The Large Helical Device(LHD) in National Institute for Fusion Science, Japan is a leading machine among helical systems. In Germany a same-sized helical device having different magnetic configuration is under construction. It is very important to collaborate with each other. The main objective of this research is to establish transport database between Japan, Germany and Spain for clarifying confinement mechanism in helical plasmas, and to promote international collaboration experiments under IEA Stellarator Implementing Agreement.Within 3-year term of this scientific research project, the following useful research collaborations have been performed.(1)Project planning and research investigation : Several researchers visited Europe and attended the IEA International Executive Stellarator Meeting for promoting the LHD International Mutual Experiment (LIME) program for high-performance and steady-state sustainment of helical plasmas.(2)Personal exchange for research collaboration : To present the results of this grant-in-aid research, a few scientists have been abroad and attended the International Conference, and discussed with foreign scientists. Especially the differences in plasma confinement, transport code development and future collaboration plans were discussed.(3)Invitation of foreign scientists related to confinement, diagnostics and reactor : Within the framework of this research, several foreign scientists from Germany, Swiss, USA, Russia and so on were invited, and a variety of collaboration researches on plasma confinement, diagnostics and reactor design were carried out, which promoted the LIME program.These research collaborations are highly evaluated in the international executive committee under International Energy Agency (IEA) Stellarator Implement Agreement.