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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

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 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:
OSTI Identifier:821558
DOE Contract Number:AC03-99ER54463
Resource Type:Conference
Data Type:
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
Research Org:GENERAL ATOMICS (US)
Sponsoring Org:(US)
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