Overview of steady state tokamak plasma experiments in TRIAM-1M
Overview of steady state tokamak plasma experiments in TRIAM-1M
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TRIAM-1M 稳态托卡马克等离子体实验概述
DOI：
10.1088/0029-5515/43/12/006
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发表时间：
2003
期刊：
影响因子：
3.3
通讯作者：
O. Mitarai
中科院分区：
文献类型：
--
作者：
H. Zushi;S. Itoh;K. Hanada;Katsuya Nakamura;M. Sakamoto;E. Jotaki;M. Hasegawa;Y. Pan;S. Kulkarni;A. Iyomasa;S. Kawasaki;H. Nakashima;N. Yoshida;K. Tokunaga;T. Fujiwara;M. Miyamoto;H. Nakano;M. Yuño;A. Murakami;S. Nakamura;N. Sakamoto;K. Shinoda;S. Yamazoe;H. Akanishi;K. Kuramoto;Y. Matsuo;A. Iwamae;T. Fuijimoto;A. Komori;T. Morisaki;H. Suzuki;S. Masuzaki;Y. Hirooka;Y. Nakashima;O. Mitarai
本文介绍了TRIAM-1 M（R_0 = 0.8 m，a × B = 0.12 m × 0.18 m，B = 8 T）稳态托卡马克研究的概况。在不使用中心螺线管线圈的情况下，重新研究了在（1-2）× 1019 m−3的中等密度区域电流上升速率的可控性。在B = 6.7 T下，等离子体由ECH（170 GHz，200 kW的基本o模式）引发，并且通过在电流上升阶段保持LH功率小于100 kW，可以实现ITER的150 kA s−1的技术限制以下的上升速率。从跃迁几率的角度对阈值功率附近的增强电流驱动（ECD）模式进行了物理理解。ECD转变的转变频率ftranss被确定为PCD的函数。在~70 kW时，对于~0.017 Hz的ftranss值没有发生跃迁，这意味着跃迁概率几乎为零。随着PCD > Pth的增加，ftranss增加到10 Hz，并且转变倾向于以高概率发生。放电持续时间的记录值在低和低功率（<10 kW）放电中更新为3 h 10 min。研究了长时间放电中的整体粒子平衡，确定了壁面抽运率随时间的变化。虽然密度低，但必须在等离子体开始后30分钟停止气体供应以保持密度恒定。之后，仅通过再循环焊剂维持密度，直到放电结束。在高功率、高密度实验中，除了再循环问题外，定域PWI还会影响托卡马克等离子体的SSO。研究了金属杂质（Fe、Cr、Ni、Mo）的增强注入对高性能ECD等离子体维持的影响。为了评估氦轰击对面向等离子体部件的影响以及未来燃烧等离子体中氢的再循环，研究了长时间氦放电对金属的微观损伤。总曝光时间为128 s。从样品的热解吸实验中，保留的氦量估计为3.9 × 1020 He m−2，SOL中的刻度长度约为1 mm。
An overview of steady state tokamak studies in TRIAM-1M (R0 = 0.8 m, a × b = 0.12 m × 0.18 m and B = 8 T) is presented. The current ramp-up scenario without using centre solenoid coils is reinvestigated with respect to controllability of the current ramp-up rate at the medium density region of (1–2) × 1019 m−3. The plasma is initiated by ECH (fundamental o-mode at 170 GHz with 200 kW) at B = 6.7 T, and the ramp-up rate below the technical limit of 150 kA s−1 for ITER can be achieved by keeping the LH power less than 100 kW during the current ramp-up phase. The physics understanding of the enhanced current drive (ECD) mode around the threshold power level has progressed from a viewpoint of transition probability. A transition frequency, ftrans, for the ECD transition is determined as a function of PCD. At ~70 kW no transition occurs for an ftrans value of ~0.017 Hz, meaning almost zero transition probability. With increasing PCD > Pth, ftrans increases up to 10 Hz, and the transition tends to occur with high probability. The record value of the discharge duration is updated to 3 h 10 min in a low and low power (<10 kW) discharge. The global particle balance in long duration discharges is investigated, and the temporal change in wall pumping rate is determined. Although the density was low, the gas supply had to be stopped at 30 min after the plasma initiation to maintain the density constant. After that the density was sustained by the recycling flux alone until the end of the discharges. In addition to the recycling problem, in the high power and high density experiments, the localized PWI affects the SSO of the tokamak plasma. The effects of enhanced influx of metal impurities (Fe, Cr, Ni, Mo) on sustainment of the high performance ECD plasma are investigated. In order to evaluate the helium bombarding effects on the plasma facing component and hydrogen recycling in the future burning plasma, microscopic damage of metals exposed to long duration helium discharges was studied. The total exposure time was 128 s. From thermal desorption experiments for the specimens the amount of retained helium was evaluated as 3.9 × 1020 He m−2 and the scale length to be ~1 mm in the SOL.