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Title: COMPLETE SUPPRESSION OF THE m/n=2/1 NEOCLASSICAL TEARING MODE USING RADIALLY LOCALIZED ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D AND THE REQUIREMENTS FOR ITER

Abstract

OAK-B135 DIII-D experiments demonstrate the first real-time feedback control of the relative location of a narrow beam of microwaves to completely suppress and eliminate a growing tearing mode at the q=2 surface. long wavelength tearing modes such as the m/n = 2/1 instability are particularly deleterious to tokamak operation. Confinement is seriously degraded by the island, plasma rotation can cease (mode-lock) and disruption can occur. The neoclassical tearing mode (NTM) becomes unstable due to the presence of a helically-perturbed bootstrap current and can be stabilized by replacing the missing bootstrap current in the island O-point by precisely located co-electron cyclotron current drive (ECCD). The geometry for the ECCD launch, the second harmonic resonance 2f{sub ce} and the q=2 surface are shown. The optimum position is found when the DIII-D plasma control system (PCS) is put into a search and suppress mode that makes small radial shifts (in about 1 cm steps) in the ECCD location based on minimizing the Mirnov amplitude.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
(US)
OSTI Identifier:
821558
DOE Contract Number:  
AC03-99ER54463
Resource Type:
Conference
Resource Relation:
Conference: IAEA TECHNICAL MEETING ON ECRH PHYSICS AND TECHNOLOGY FOR ITER, KLOSTER-SEEON (DE), 07/14/2003--07/16/2003; Other Information: PBD: 1 Jun 2003
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; BOOTSTRAP CURRENT; CONFINEMENT; CONTROL SYSTEMS; CYCLOTRONS; DOUBLET-3 DEVICE; ELECTRONS; FEEDBACK; GEOMETRY; HARMONICS; IAEA; INSTABILITY; PHYSICS; RESONANCE; ROTATION; WAVELENGTHS

Citation Formats

LA HAYE, RJ, LUCE, TC, PETTY, CC, HUMPHREYS, DA, HYATT, AW, PERKINS, FW, PRATER, R, STRAIT, EJ, and WADE, MR. COMPLETE SUPPRESSION OF THE m/n=2/1 NEOCLASSICAL TEARING MODE USING RADIALLY LOCALIZED ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D AND THE REQUIREMENTS FOR ITER. United States: N. p., 2003. Web.
LA HAYE, RJ, LUCE, TC, PETTY, CC, HUMPHREYS, DA, HYATT, AW, PERKINS, FW, PRATER, R, STRAIT, EJ, & WADE, MR. COMPLETE SUPPRESSION OF THE m/n=2/1 NEOCLASSICAL TEARING MODE USING RADIALLY LOCALIZED ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D AND THE REQUIREMENTS FOR ITER. United States.
LA HAYE, RJ, LUCE, TC, PETTY, CC, HUMPHREYS, DA, HYATT, AW, PERKINS, FW, PRATER, R, STRAIT, EJ, and WADE, MR. 2003. "COMPLETE SUPPRESSION OF THE m/n=2/1 NEOCLASSICAL TEARING MODE USING RADIALLY LOCALIZED ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D AND THE REQUIREMENTS FOR ITER". United States. https://www.osti.gov/servlets/purl/821558.
@article{osti_821558,
title = {COMPLETE SUPPRESSION OF THE m/n=2/1 NEOCLASSICAL TEARING MODE USING RADIALLY LOCALIZED ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D AND THE REQUIREMENTS FOR ITER},
author = {LA HAYE, RJ and LUCE, TC and PETTY, CC and HUMPHREYS, DA and HYATT, AW and PERKINS, FW and PRATER, R and STRAIT, EJ and WADE, MR},
abstractNote = {OAK-B135 DIII-D experiments demonstrate the first real-time feedback control of the relative location of a narrow beam of microwaves to completely suppress and eliminate a growing tearing mode at the q=2 surface. long wavelength tearing modes such as the m/n = 2/1 instability are particularly deleterious to tokamak operation. Confinement is seriously degraded by the island, plasma rotation can cease (mode-lock) and disruption can occur. The neoclassical tearing mode (NTM) becomes unstable due to the presence of a helically-perturbed bootstrap current and can be stabilized by replacing the missing bootstrap current in the island O-point by precisely located co-electron cyclotron current drive (ECCD). The geometry for the ECCD launch, the second harmonic resonance 2f{sub ce} and the q=2 surface are shown. The optimum position is found when the DIII-D plasma control system (PCS) is put into a search and suppress mode that makes small radial shifts (in about 1 cm steps) in the ECCD location based on minimizing the Mirnov amplitude.},
doi = {},
url = {https://www.osti.gov/biblio/821558}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 2003},
month = {Sun Jun 01 00:00:00 EDT 2003}
}

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