Sheared flows and transition to improved confinement regime in the TJ-II stellarator

被引：105

作者：

Estrada, T. ^{[1
]}

Happel, T. ^{[1
]}

Eliseev, L. ^{[2
]}

Lopez-Bruna, D. ^{[1
]}

Ascasibar, E. ^{[1
]}

Blanco, E. ^{[1
]}

Cupido, L. ^{[3
]}

Fontdecaba, J. M. ^{[1
]}

Hidalgo, C. ^{[1
]}

Jimenez-Gomez, R. ^{[1
]}

Krupnik, L. ^{[4
]}

Liniers, M. ^{[1
]}

Manso, M. E. ^{[3
]}

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

Medina, F. ^{[1
]}

Melnikov, A. ^{[2
]}

van Milligen, B. ^{[1
]}

Ochando, M. A. ^{[1
]}

Pastor, I. ^{[1
]}

Pedrosa, M. A. ^{[1
]}

Tabares, F. L. ^{[1
]}

Tafalla, D. ^{[1
]}

机构：

[1] As EURATOM CIEMAT, Lab Nacl Fus, Madrid 28040, Spain

[2] RNC Kurchatov Inst, Inst Nucl Fus, Moscow, Russia

[3] As EURATOM IST, Inst Plasmas & Fusao Nucl, Lisbon, Portugal

[4] NSC KIPT, Inst Plasma Phys, UA-310108 Kharkov, Ukraine

来源：

PLASMA PHYSICS AND CONTROLLED FUSION | 2009年 / 51卷 / 12期

关键词：

RADIAL ELECTRIC-FIELD; H-MODE; VELOCITY SHEAR; DOPPLER REFLECTOMETRY; PROFILE MEASUREMENTS; POLOIDAL ROTATION; ZONAL FLOWS; PLASMA; TURBULENCE; TRANSPORT;

D O I：

10.1088/0741-3335/51/12/124015

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：

Sheared flows have been experimentally studied in TJ-II plasmas. In low-density ECH plasmas, sheared flows can be easily controlled by changing the plasma density, thereby allowing the radial origin and evolution of the edge velocity shear layer to be studied. In high density NBI heated plasmas a negative radial electric field is observed that is dominated by the diamagnetic component. The shear of the negative radial electric field increases at the L-H transition by an amount that depends on the magnetic configuration and heating power. Magnetic configurations with and without a low order rational surface close to the plasma edge show differences that may be interpreted in terms of local changes in the radial electric field induced by the rational surface that could facilitate the L-H transition. Fluctuation measurements show a reduction in the turbulence level that is strongest at the position of maximum E(r) shear. High temporal and spatial resolution measurements indicate that turbulence reduction precedes the increase in the mean sheared flow, but is simultaneous with the increase in the low frequency oscillating sheared flow. These observations may be interpreted in terms of turbulence suppression by oscillating flows, the so-called zonal flows.

引用

页数：11

共 29 条

[1] Evolution of the radial electric field in a JET H-mode plasma [J].