New physics capabilities from the upgraded Thomson scattering diagnostic on MAST

被引：27

作者：

Gibson, K. J. ^{[1
]}

Barratt, N. ^{[1
]}

Chapman, I. ^{[2
]}

Conway, N. ^{[2
]}

Dunstan, M. R. ^{[2
]}

Field, A. R. ^{[2
]}

Garzotti, L. ^{[2
]}

Kirk, A. ^{[2
]}

Lloyd, B. ^{[2
]}

Meyer, H. ^{[2
]}

Naylor, G. ^{[2
]}

O'Gorman, T. ^{[2
,3
]}

Scannell, R. ^{[2
]}

Shibaev, S. ^{[2
]}

Snape, J. ^{[1
]}

Tallents, G. J. ^{[1
]}

Temple, D. ^{[2
,4
]}

Thornton, A. ^{[1
]}

Pinches, S. ^{[2
]}

Valovic, M. ^{[2
]}

Walsh, M. J. ^{[2
]}

Wilson, H. R. ^{[1
]}

机构：

[1] Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England

[2] EURATOM CCFE Fus Assoc, Culham Sci Ctr, Abingdon, Oxon, England

[3] Assoc Euratom DCU, Univ Coll Cork, Dept Phys, Cork, Ireland

[4] Univ London Imperial Coll Sci Technol & Med, Dept Phys, London, England

来源：

PLASMA PHYSICS AND CONTROLLED FUSION | 2010年 / 52卷 / 12期

基金：

英国工程与自然科学研究理事会;

关键词：

TEARING MODES; MAGNETIC ISLANDS; PLASMA; TOKAMAK; DYNAMICS;

D O I：

10.1088/0741-3335/52/12/124041

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 newly upgraded MAST Thomson scattering (TS) system provides excellent spatial resolution (similar to 1 cm) at over 130 radial locations across a full plasma diameter, and utilizes eight individual Nd: :YAG laser systems which can be fired sequentially, providing electron temperature and density profiles approximately every 4ms throughout a plasma discharge. By operating the system in burst mode, whereby the laser separation can be adjusted to within a few microseconds of each other, it is possible to obtain detailed profiles of transient and periodic phenomena such as sawteeth crashes, massive gas injection for disruption mitigation and the temperature perturbations associated with neoclassical tearing mode (NTM) islands. Following Fitzpatrick et al (1995 Phys. Plasmas 2 825), we consider a simplified model in which finite parallel diffusive heat transport can provide a threshold for NTM island growth and demonstrate that the TS derived electron temperature profiles around an island can be used to obtain both the island width and the critical island width below which temperature gradients are maintained across the island, potentially removing the bootstrap current drive for the NTM. Initial results from high beta, neutral beam injection heated discharges on MAST show that the measured island width inferred from the TS data is in good agreement with magnetic estimates of the island width (considering both a cylindrical approximation and using a full field line tracing estimate). The temporal behaviour of the island width obtained from the magnetic diagnostics indicates that for the scenarios considered to date, finite parallel diffusion is likely to play an important role in NTM threshold physics in MAST.

引用

页数：11

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