DC HELICITY INJECTION AND MHD RELAXATION STUDIES IN AN RFP BY MAKING USE OF INSULATED SEGMENTS OF DISCHARGE CHAMBER

利用放电室绝缘段在 RFP 中进行直流螺旋注入和 MHD 弛豫研究

• 批准号: 05680394
• 负责人: MASAMUNE Sadao
• 金额: $ 1.28万
• 依托单位: KYOTO INSTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05680394/
• 关键词: REVERSED-FIELD PINCH; MAGNETIC HELICITY; NONINDUCTIVE CURRENT DRIVE; DC HELICITY INJECTION; MHD RELAXATION; MHD INSTABILITY CONTROL; STE-2 RFP; STE-2 RFP

It is one of the objectives of this research project to search for the possibility of DC helicity injection scheme in an RFP by taking advantage of the insulated segments of the discharge chamder of the STE-2 RFP.The other includes the MHD relaxation process associated with the helicity injection. Experiments in STE-2 with standard RFP and ultra-low-q (ULQ) plasmas have provided the following results.(1) DC helicity injection was performed with the use of metal electrodes inserted at the edge. The electrodes were made of stainlewss steel with surface area of 0.8 cm2. These two electrodes were inserted at the same toroidal location, separated by 270ﾟ poloidally. The maximum voltage applied was 400 V with a current a current of 100 A.The injected current density was roughly equal to the average toroidal current density. A slight (5 %) increase of the toroidal magnetic flux was observed in the vicinity of the electrodes. This toroidally localized flux increase did not depend upon the pola … More rity of the applied voltage, which was contradictory to the expectation based on the helicity balance relation. No appreciable increase was observed either in the edge poloidal field or in the edge toroidal field. The results may indicate that increased local beta value due to localized Joule heatinh plays important role in plasma response.(2) DC helicity injection was made by applying voltage between the insulated segments of the chamber and simultaneously by spatially modulating the toroidal field so as to produce the magnetic flux penetrating these segments. This method was applied only to medium-current (20 kA) ULQ plasmas because of the deleterious effect of the toroidal field modulation on RFP discharges. The plasma current measured at the chamber poloidal gap has increased by 20 % with the applied voltage of 1.3 kV.A further optimization of RFP discharge is in progress by reducing field errors at the gap with the help of localized conducting shell. The new scheme DC helicity injection will be applied to the improved RFP discharges. Less

本研究计划的目的之一是利用STE-2型RFP放电室的绝缘段，探索RFP中直流螺旋度注入方案的可能性，另一个目的是研究与螺旋度注入相关的MHD弛豫过程。在STE-2中使用标准RFP和超低q（ULQ）等离子体的实验提供了以下结果。(1)DC螺旋度注入使用插入在边缘处的金属电极来进行。电极由表面积为0.8cm 2的不锈钢制成。这两个电极被插入在相同的环形位置，以270 °螺旋线分开。施加的最大电压为400 V，电流为100 A。注入的电流密度大致等于平均环形电流密度。在电极附近观察到环形磁通量的轻微（5%）增加。这种环形局部磁通量的增加并不依赖于磁极 ...更多信息 这与基于螺旋度平衡关系的预期相矛盾。在边缘极向场或边缘环向场中没有观察到明显的增加。结果表明，局部焦耳加热引起的局部β值的增加在等离子体响应中起重要作用。(2)直流螺旋度注入是通过在腔室的绝缘段之间施加电压，同时通过空间调制环向场以产生穿过这些段的磁通量来进行的。这种方法只适用于中等电流（20 kA）ULQ等离子体，因为RFP放电的环向场调制的有害影响。当外加电压为1.3 kV时，在腔室极向间隙处测得的等离子体电流增加了20%。通过局部导电壳的帮助，减小了差距处的场误差，进一步优化了RFP放电。新方案直流螺旋度注入将应用于改进的RFP放电。少

项目成果

D.Ishijima, S.Masamune, M.Iida, A.Mori, T.Miyagi, H.Oshiyama: "Reduction of Anomalous Resistance in an RFP with Improved Shell Proximity" J.Phys. Soc. Jpn.Vol.63. 3899-3900 (1994)

D.Ishijima、S.Masamune、M.Iida、A.Mori、T.Miyagi、H.Oshiyama：“通过改进外壳邻近性减少 RFP 中的异常电阻”J.Phys。

D.Ishijima: "Reduction of Anomalous Resistance in an RFP with Improved shell Proximity" J.Phys.Soc.Jpn.63. 3899-3900 (1994)

D.Ishijima：“通过改进外壳邻近性减少 RFP 中的异常电阻”J.Phys.Soc.Jpn.63。

S.Masamune: "Boundary Condition Studies in a Peversed Field Pinch" Abstracts for the 6th Int.Toki Conf.on Plasma Phys.Controlled Nuclear Fusion. 37- (1994)

S.Masamune：“Pevered Field Pinch 中的边界条件研究”第六届 Int.Toki Conf.on Plasma Phys.Controlled Nuclear Fusion 摘要。

S.Masamune: "Boundary Condition Studies in a Reversed Field Pinch" Abstracts for the 6th Int.Conf.Toki on Plasma Phys.Ctr.N.F.37-37 (1994)

S.Masamune：“反向场夹断中的边界条件研究”摘要，第六届 Int.Conf.Toki on Plasma Phys.Ctr.N.F.37-37 (1994)

M.Iida: "First Results from the Poloidal Divertor Experiment in the STE-2 RFP" Plasma Phys.Control.Fusion. 36. 153-161 (1994)

M.Iida：“STE-2 RFP 中极向偏滤器实验的第一个结果”等离子 Phys.Control.Fusion。