ITER asymmetric error fields and their correction

Leuer, J.A.; Haye, R. J. La; Kellman, A.G.; Humphreys, D.A.; Scoville, J. T.; Gribov, Y.; Wesley, J.C.; Hender, T. C.; Doinikov, N.I.

doi:10.1109/fusion.1997.687089

Cited by 7 publications

(10 citation statements)

References 5 publications

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“…To suppress error fields to the limit, which reduces the probability of locked modes and associated disruptions, a correction coil (CC) system has been designed [8]. The CC system consists of three For a tokamak with 18 TF coils, each CC set has six coils.…”

Section: The Correction Coil Systemmentioning

confidence: 99%

“…The probability of a three-mode error field is determined by the 'weighted' Rayleigh distribution [8]. The probability density function for a three-mode error field can be derived from equations (11), (19), (20) and (21): Table 1 shows the statistical expectation of the amplitudes of different error field modes.…”

Section: Statistical Probability Distributions Of Expected (Mn) Erromentioning

confidence: 99%

“…The following criterion for the allowable error field was adopted on the basis of the experimental data [1][2][3]8] shown in figure 1:…”

Section: Statistical Probability Distributions Of Expected (Mn) Erromentioning

confidence: 99%

“…To assess the asymmetric error fields anticipated in tokamak magnet systems, a statistical approach is applicable [1][2][3][4][5][6][7][8]. The main contributors to error fields in existing tokamaks are deviations of the toroidal field (TF) and poloidal field (PF) coils and the central solenoid (CS) sections from their design positions.…”

Section: Introductionmentioning

confidence: 99%

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Statistical analysis of expected error fields in tokamaks and their correction

Amoskov

Белов

Belyakov

et al. 2005

Plasma Devices and Operations

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Error fields in tokamak magnet systems are primarily associated with displacements of toroidal field and poloidal field coils, arising during their manufacture and assembly. The Fourier analysis of error fields on a rational magnetic flux surface, anticipated in the ITER machine, exhibited the lowerorder modes ((m,n) = (1,1), (2,1), (3,1)) of error fields as the most crucial ones. A statistical study using the Monte Carlo simulations has demonstrated that an averaged three-mode error field from the superposition of coil displacements can be two to three times higher than the acceptable level. The estimates obtained have been used to assess the capability of the correction coil system.

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Section: The Correction Coil Systemmentioning

confidence: 99%

Section: Statistical Probability Distributions Of Expected (Mn) Erromentioning

confidence: 99%

“…The following criterion for the allowable error field was adopted on the basis of the experimental data [1][2][3]8] shown in figure 1:…”

Section: Statistical Probability Distributions Of Expected (Mn) Erromentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Statistical analysis of expected error fields in tokamaks and their correction

Amoskov

Белов

Belyakov

et al. 2005

Plasma Devices and Operations

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“…Methodology for performing error field analysis and error field correction was first established for ITER in 1997 [9]. Fourier harmonics of the external magnetic perturbations are developed using the magnetic flux coordinates ( , Â, ϕ), where is the total poloidal magnetic flux defining magnetic surfaces = const, ϕ is the conventional toroidal angle, and Â is the associated straight field line angle [10].…”

Section: Error Fields Calculationmentioning

confidence: 99%

ITER non-axisymmetric error fields induced by its magnet system

Knaster

Amoskov

Formisano

et al. 2011

Fusion Engineering and Design

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Study of in-vessel nonaxisymmetric ELM suppression coil concepts for ITER

et al. 2008

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Large Type-I edge-localized mode (ELM) heat pulses may limit the life of divertor targets in a burning plasma. Recent experiments show that pitch-resonant nonaxisymmetric magnetic perturbations of the plasma edge of 0.0005 or less of the main magnetic field offer a useful solution, but there is little room in the presently designed ITER for even small perturbation coils. We present proposed coil requirements for ITER ELM suppression, derived primarily from DIII-D ELM suppression experiments. We show by calculated examples that large arrays of coils (e.g. four toroidal rows of nine coils each) on the outboard wall near the plasma (at the radius of the blanket-vacuum vessel interface R ∼ 8 m) can meet the known requirements, expressed in terms of the toroidal helical Fourier harmonic spectrum, for both low- and high-q ITER plasmas, when coil currents are distributed to concentrate the magnetic perturbation into a single dominant Fourier spectral peak. Fields from arrays of less than four rows of nine coils (a) penetrate relatively more strongly into the core plasma, and (b) generate more and larger nonresonant spectral peaks. Both features are expected to brake desirable plasma rotation. We found that the Moiré effect from approximating sinusoidal perturbations by a limited discrete coil set can be used to control nonfundamental harmonics in large arrays. We show that a judicious choice of current distribution among the coils ameliorates effects of an 80° toroidal gap where no coils are allowed in the ITER midplane.

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ITER asymmetric error fields and their correction

Cited by 7 publications

References 5 publications

Statistical analysis of expected error fields in tokamaks and their correction

Statistical analysis of expected error fields in tokamaks and their correction

ITER non-axisymmetric error fields induced by its magnet system

Study of in-vessel nonaxisymmetric ELM suppression coil concepts for ITER

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