Numerical modeling of diffusive heat transport across magnetic islands and local stochastic field

Yu, Q.

doi:10.1063/1.2206788

Cited by 51 publications

(67 citation statements)

References 33 publications

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“…Dedicated numerical methods are utilized in the code to keep the numerical error at very low level even for high values of S and χ || /χ ⊥ [41][42][43]. The corresponding time evolution of the mode frequency is shown in figure 2 by the solid (dashed) curve for ψ a =5×10 -8 (10 -7 ).…”

Section: Numerical Resultsmentioning

confidence: 99%

Locking of neoclassical tearing modes by error fields and its stabilization by RF current

Günter

2008

Nucl. Fusion

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The locking of neoclassical tearing modes (NTMs) by error fields is studied numerically. In the regime with low mode frequency and large plasma viscosity, the required field amplitude for mode locking is found to be proportional to the plasma viscosity and the mode frequency but inversely proportional to the square of the magnetic island width and the Alfven velocity, being similar to that of the classical tearing mode. This indicates that NTMs will be locked to low amplitude error fields in a fusion reactor. The stabilization of NTMs by RF current in the presence of a static helical field is therefore further investigated. The applied helical field allows to control the location of the island's o-point to be in the RF wave deposition region, to enable the NTM stabilization by RF current after mode locking. When the island is large enough to be locked by a small amplitude helical field in the desired phase, the island is reduced to a smaller width by RF current compared to the case without the helical field. This suggests a possible way to enhance the stabilization of NTMs by RF current.

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Section: Numerical Resultsmentioning

confidence: 99%

Locking of neoclassical tearing modes by error fields and its stabilization by RF current

Günter

2008

Nucl. Fusion

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“…In typical parameters of LHD experiments, the collisionality is expected the Rechester-Rosenbluth (RR) regime in the region expected stochastically because χ || /χ ⊥ ∼ 10 6 [9][10][11]. The radial heat conductivity due to the stochasticity of field lines is given by…”

Section: Radial Heat Diffusivity Due To Stochastic Field Linesmentioning

confidence: 99%

Effects of the Stochasticity on Transport Properties in High-β LHD

Suzuki

Watanabe

Funaba

et al. 2009

Plasma and Fusion Research

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Effects of the stochasticity of magnetic field lines on transport properties are investigated. In a high-β LHD plasma, the structure of field lines in the peripheral region becomes stochastic by finite-β effects but the finite pressure gradient exists in that region. The radial diffusion coefficient and the Kolmogorov length of stochastic field lines are estimated. In the stochastic region, the radial diffusion of stochastic field lines becomes large and the Kolmogorov length becomes short due to increasing β. In that region, the radial heat transport becomes large due to the stochasticity of field lines.

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“…Heat transport analysis.-Heretofore heat transport in configurations with magnetic islands has been analyzed analytically and numerically by neglecting heat sources inside islands [13][14][15][16]. In this Letter we take these into account by applying analytical approaches.…”

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Elucidation of the Heat-Flux Limit from Magnetic-Island Heating

Tokar

Gupta

2007

Phys. Rev. Lett.

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Recent experiments on heating of magnetic islands in a tokamak are analyzed to assess plasma transport characteristics. By comparing with the experimental data, both perpendicular and parallel components of the electron heat conductivity in the island are determined. As a consequence, the so-called heat-flux limit factor , the ratio of the parallel heat conduction flux in a collisionless plasma to that transferred by freestreaming electrons, can be estimated. The found factor does not contradict that established earlier by interpreting laser plasma experiments.

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Numerical modeling of diffusive heat transport across magnetic islands and local stochastic field

Cited by 51 publications

References 33 publications

Locking of neoclassical tearing modes by error fields and its stabilization by RF current

Locking of neoclassical tearing modes by error fields and its stabilization by RF current

Effects of the Stochasticity on Transport Properties in High-β LHD

Elucidation of the Heat-Flux Limit from Magnetic-Island Heating

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