Developments of Laser-Aided Plasma Diagnostics for Fusion Plasmas

在核核聚变研究中，已经达到了破平衡等离子体条件，正在为真正的D-T聚变燃烧实验做准备。在这里，氚处理和壁材的中子诱导放射性是最关键的问题，实现远程处理一直是人们追求的目标。对于等离子体诊断，有必要从有限的端口访问中获取尽可能多的数据。本研究计划测试由现任首席研究员及其合作者开发的激光辅助等离子体诊断对JET等离子体的影响。JET项目计划进行一次真正的DT聚变燃烧实验。研究的内容有三个方面。(1)激光雷达汤姆逊散射用于测量电子温度（T_e）和密度（n_e）通常需要较大的激光输入/输出端口和一个散射观测端口。然而，将这些端口安装到聚变燃烧等离子体机器上是很困难的，因为……氚增殖毯和超导磁体的存在更多。激光雷达汤姆逊散射在很大程度上解决了这一难题，在过去的十年里，九州大学的研究小组与JET进行了合作研究。本研究分为两部分。一是常规可靠地测量核心等离子体中的T_e和n_e。这是非常成功的，因为核心激光雷达系统现在以90mm的空间分辨率在2hz下提供T_e和n_e的数据。此外，用于提高空间分辨率的条纹相机系统也取得了成功，获得了50毫米的空间分辨率。另一方面，由于激光和探测光学的对准困难，激光雷达系统在观察分流区时还没有产生散射信号。本次合作研究结束后，将开展进一步的合作研究。(2)集体汤姆逊散射对1995年获得的第一批集体汤姆逊散射数据进行了深入的分析，并提出了改进的方向。本研究的重大影响是由日本、欧洲和美国的研究人员组成了利用CO_2激光进行集体汤姆森散射的研究小组，并于1996年12月进行了第一次活动。讨论了JAERI JT-60U的实际测量计划，实验将从1998财政年度开始。在这项合作研究的执行过程中，p.e.s ott博士和现任首席研究员之间的相互信任，与普林斯顿大学的k.l young博士一起组成了ITER（国际热核实验堆）诊断专家组。目前的合作研究工作已反映在该专家组的活动中，并组织了国际会议。少

In the rmonuclear fusion research, the breskeven plasma condition has been attained, and preparations are underway for the real D-T fusion burning experiments. Here, tritium handling and neutron-induced radioactivity of wall materials are the most cirtical issues, and realization of remote handling has been pursued. Regarding the plasma diagnostics, it is necessary to get as many data as possible from limited port access.This research was planned to test the laser-aided plasma diagnostics, which had been developed by the present principal investigator and his collaborators, to JET plasmas. The JET project plans to undertake a real DT fusion-burning experiment.The contents of the research are three-folds.(1) LIDAR Thomson scatteringThomson scattering for measurements of electron temperature (T_e) and density (n_e) usually requires large laser input/output ports and a scattering observation ports. However, it is difficult to install these ports to a fusion burning plasma machine, because … More of the presence of tritium breeding blankets and superconducting magnets. LIDAR Thomson scattering mostly solves this difficulty, and the collaborative research has been carried out between the group of Kyusyu University and JET for the last ten years.The researches are divided into two studies. One is to measure T_e and n_e in the core plasmas routinely and reliably. This has been very successful, as the core LIDAR system is now routinely supplying data of T_e and n_e at the spatial resolution of 90 mm at 2 Hz. Also, the streak camera system for improving the spatial resolutuin is working successfully, yielding the spatial resolution of 50 mm. On the other hand, the LIDAR system looking at the divertor region is yet to produce scattering signal, because of the difficulty of alignment of the laser and detection optics. Further collaborative studies will be carried out after the termination of this collaboration study.(2) Collective Thomson scatteringThe first data of collective Thomson scattering, oftained in 1995, have been thoroughly analyzed, and the directions of improvement have been considered.The big impact of the present research is the formation of study group of the collective Thomson scattering using a CO_2 laser formed by the Japanese, European and American researchers, and the first activity took place in December 1996. Actual measurement plans on JT-60U at JAERI were discussed, and the experiment will start from the fiscal year 1998.(3) Planning of burning plasm diagnostics in generalThoughout the execution of this collabrative research, the mutual trust of Dr.P.E.Stott and the present principal inrstigator has brought about the formation of the Expert Group of Diagnostics for ITER (International Thermonuclear Experimental Reactor), together with Dr.K.Young of Princeton University. The work in the present collaborative research has been reflected in this Expert Group activities, and international meetings have been organized. Less