MHD stability of optimized shear discharges in JET

被引:75
作者
Huysmans, GTA [1 ]
Hender, TC
Alper, B
Baranov, YF
Borba, D
Conway, GD
Cottrell, GA
Gormezano, C
Helander, P
Kwon, OJ
Nave, MFF
Sips, ACC
Söldner, FX
Strait, EJ
Zwingmann, WP
机构
[1] Jet Joint Undertaking, Abingdon OX14 3EA, Oxon, England
[2] UKAEA Euratom Fus Assoc, Culham Sci Ctr, Abingdon OX14 3DB, Oxon, England
[3] EURATOM Assoc, IST, Lisbon, Portugal
[4] Taegu Univ, Taegu, South Korea
[5] Gen Atom Co, San Diego, CA USA
关键词
D O I
10.1088/0029-5515/39/11/301
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
The main limitation to the performance of JET optimized shear (OS) discharges is due to MHD instabilities, mostly in the form of a disruptive limit. The structure of the MHD mode observed as a precursor to the disruption, as measured from SXR and ECE diagnostics, shows a global ideal MHD mode. The measured mode structure is in good agreement with the calculated mode structure of the pressure driven kink mode. The disruptions occur at relatively low normalized beta (1 < beta(N) < 2), in good agreement with calculated ideal MHD stability limits for the n = 1 pressure driven kink mode. These low limits are mainly due to the extreme peaking factor of the pressure profiles. Other MHD instabilities observed in JET OS discharges include, usually benign, chirping modes. These modes, which occur in bursts during which the frequency changes, have the same mode structure as the disruption precursor but are driven unstable by fast particles.
引用
收藏
页码:1489 / 1507
页数:19
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