H-mode access in the low density regime on JET
H-mode access in the low density regime on JET
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DOI：
10.1088/0741-3335/48/4/001
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发表时间：
2006-04
影响因子：
2.2
通讯作者：
Y. Andrew;R. Sartori;E. Righi;E. de la Luna;S. Hacquin;D. Howell;N. Hawkes;L. Horton;A. Huber;A. Korotkov;M. O’Mullane
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文献类型：
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作者：
Y. Andrew;R. Sartori;E. Righi;E. de la Luna;S. Hacquin;D. Howell;N. Hawkes;L. Horton;A. Huber;A. Korotkov;M. O’Mullane
1在极低等离子体密度条件下的H模式接入研究提供了关于边缘输运势垒形成的物理学的有价值的信息，并且是下一步聚变装置ITER的操作方案开发的重要部分。在边缘电子密度很低的情况下，使用MkII气箱隔膜偏滤器的JET操作被发现对L-H跃迁的功率阈值Pth有显著影响。当Ip/Bt值为2.5 MA/2.7 T、2.5 MA/2.6 T、2.5 MA/2.4 T和2.2 MA/2.4 T时，出现了一个急剧的转折点，在该转折点以下，Pth随下降而增加。基座电子温度表现出与Pth非常相似的边缘依赖性。还考虑了Zeff在H模功率阈值随密度变化中的作用。在2.5 MA/2.7 T和2.5 MA/2.6 T条件下，将存在偏滤器隔膜的拍摄与使用MkII GB隔膜置换板偏滤器运行的相同扫描进行比较。这项调查的结果表明，去除隔膜可能降低了PTH的“转折点”。
1 H-mode access studies under conditions of very low plasma density provide valuable information on the physics of the edge transport barrier formation and are an important part of the operational scenario development for the next step fusion device, ITER. JET operation with a very low edge electron density, , with the MkII gas box septum divertor was found to have a significant effect on the power threshold for the L–H transition, Pth. A sharp ‘turning point’ below which Pth increases with decreasing is found for Ip/Bt values of 2.5 MA/2.7 T, 2.5 MA/2.6 T, 2.5 MA/2.4 T and 2.2 MA/2.4 T. The pedestal electron temperature demonstrates a very similar dependence on the edge as Pth. The role of Zeff in the variation of the H-mode power threshold with density is also considered. Shots with the divertor septum present are compared with an identical scan, run with the MkII GB septum replacement plate divertor at 2.5 MA/2.7 T and 2.5 MA/2.6 T. The results from this investigation indicate that removal of the septum may have lowered the ‘turning point’ for Pth.