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 [electronic resource].

Published:: San Diego, Calif. : General Atomic Company, 2003.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description:: 8 pages : digital, PDF file
Additional Creators:: General Atomic Company and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

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.

Report Numbers:

E 1.99:821558

Subject(s):

Particle Accelerators

Other Subject(s):

Note:

Published through SciTech Connect.
06/01/2003.
IAEA TECHNICAL MEETING ON ECRH PHYSICS AND TECHNOLOGY FOR ITER, KLOSTER-SEEON (DE), 07/14/2003--07/16/2003.
PRATER,R; HUMPHREYS,DA; HYATT,AW; LUCE,TC; PERKINS,FW; PETTY,CC; STRAIT,EJ; WADE,MR; LA HAYE,RJ.
(US)

Funding Information:

AC03-99ER54463

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