Electric and magnetic structure of tokamak edge plasma with static and rotating helical magnetic limiter

Takamura, S.; Shen, Yonghang; Yamada, Hiroyuki; Miyake, Masaaki; Tamakoshi, T.; Okuda, Takayoshi

doi:10.1016/0022-3115(89)90341-3

Cited by 27 publications

(18 citation statements)

References 8 publications

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“…[4][5][6][7] However, this initial expectation has been rather frustrated by a series of experimental results obtained in many tokamaks in which ergodic limiters were mounted, which often pointed out to a nonuniform distribution of field lines hitting the tokamak wall. [8][9][10][11][12][13] The term magnetic footprints has been coined to indicate the deposition pattern of field lines in the tokamak wall. 14 It should be remarked that the information conveyed by the magnetic footprints does not reflect necessarily the actual pattern of particle loading, but only a lowest-order description ͑guiding-center motion͒ which can be improved by adding drift and curvature effects.…”

Section: Introductionmentioning

confidence: 99%

Effects of the resonant modes on the magnetic footprint patterns in a tokamak wall

et al. 2006

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Magnetic footprints, or deposition patterns of chaotic magnetic field lines in a tokamak wall, are studied for a configuration with resonant modes due to an ergodic limiter. The formation of magnetic footprints using a nontwist symplectic mapping for a nonmonotonic safety factor radial profile is investigated numerically. The radial position of the resonant mode we focus on changes drastically the magnetic footprints. Deeper resonant modes produce a concentrated field line deposition pattern, whereas a resonant mode closer to the plasma edge yields a broader deposition pattern. Although these shearless equilibria can present robust transport barriers, the magnetic footprints are still present and can deteriorate the plasma confinement quality.

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Section: Introductionmentioning

confidence: 99%

Effects of the resonant modes on the magnetic footprint patterns in a tokamak wall

et al. 2006

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“…24 Devices based on this concept have been tested on several machines. 19,[21][22][23][25][26][27] However, further experiments have revealed that the heat and particle deposition patterns are not actually uniform as previously assumed, but are rather strongly structured, presenting a self-similarity that suggests an underlying fractal structure. [28][29][30][31][32][33][34][35] These structured patterns of the heat and particle deposition turn out to be undesirable from the point of view of controlling plasma-wall interactions, and have been investigated in a series of experiments with the dynamic ergodic divertor.…”

Section: Introductionmentioning

confidence: 99%

Escape patterns of chaotic magnetic field lines in a tokamak with reversed magnetic shear and an ergodic limiter

et al. 2008

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Escape patterns of chaotic magnetic field lines in a tokamak with reversed magnetic shear and an ergodic limiter PHYSICS OF PLASMAS, v.15, n.9, 2008 http://producao.usp.br/handle/BDPI/15972 The existence of a reversed magnetic shear in tokamaks improves the plasma confinement through the formation of internal transport barriers that reduce radial particle and heat transport. However, the transport poloidal profile is much influenced by the presence of chaotic magnetic field lines at the plasma edge caused by external perturbations. Contrary to many expectations, it has been observed that such a chaotic region does not uniformize heat and particle deposition on the inner tokamak wall. The deposition is characterized instead by structured patterns called magnetic footprints, here investigated for a nonmonotonic analytical plasma equilibrium perturbed by an ergodic limiter. The magnetic footprints appear due to the underlying mathematical skeleton of chaotic magnetic field lines determined by the manifold tangles. For the investigated edge safety factor ranges, these effects on the wall are associated with the field line stickiness and escape channels due to internal island chains near the flux surfaces. Comparisons between magnetic footprints and escape basins from different equilibrium and ergodic limiter characteristic parameters show that highly concentrated magnetic footprints can be avoided by properly choosing these parameters.

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“…A number of experiments have been conducted in various devices in order to explore an optimization of the divertor configuration with the stochastic magnetic boundary, e.g. in TEXT [10,11,12], CSTN-II, III, IV [13,14,15] and HYBTOK-II [16,17], Tore Supra [18,19,20], TEXTOR-DED [21,22,23], Heliotron-E [6,7], LHD [24,25,26,27],etc. Many interesting features concerning energy/particle/impurity transport and its impact on divertor functions were found.…”

Section: Introductionmentioning

confidence: 99%

Modelling of Divertor Plasma Transport in Stochastic Magnetic Boundary

Kobayashi¹

2010

AIP Conference Proceedings

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Electric and magnetic structure of tokamak edge plasma with static and rotating helical magnetic limiter

Cited by 27 publications

References 8 publications

Effects of the resonant modes on the magnetic footprint patterns in a tokamak wall

Effects of the resonant modes on the magnetic footprint patterns in a tokamak wall

Escape patterns of chaotic magnetic field lines in a tokamak with reversed magnetic shear and an ergodic limiter

Modelling of Divertor Plasma Transport in Stochastic Magnetic Boundary

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