Plasma confinement with a transport barrier

Tamano, T.; Katanuma, I.

doi:10.1088/0029-5515/41/12/307

Cited by 29 publications

(44 citation statements)

References 7 publications

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“…These evaluations indicate that the phase change of the reflectometer is less sensitive to the density profile between the cut-off layer and antenna as pointed out above. Therefore, the difference in the radial displacement of the cut-off layer is one of the reasons for the different sizes of the ELMs, which is qualitatively consistent with the stability analyses in JT-60U [20,21] describing the relation between ELM size and radial extent of the mode structure.…”

Section: Collapse Phasesupporting

confidence: 84%

Fast dynamics of type I ELMs and transport of the ELM pulse in JT-60U

et al. 2004

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Simultaneous fast ELM measurements using a reflectometer, interferometers, D α intensity and a magnetic probe reveal the detailed characteristics of type I ELMs. From the phase signal of the reflectometer indicating the radial movement of the cut-off layer, four different phases in the ELM event, i.e. a precursor phase, collapse phase, recovery phase and a relaxation phase, were observed. In the collapse phase, the radial extent of the collapse of the density pedestal reached up to twice the pedestal width. A fast drop of the horizontal interferometer signal was observed, while the vertical interferometer on the high-field side edge plasma only exhibited a small and delayed reduction. These features of the plasma response due to ELMs might indicate a non-uniform collapse of the density pedestal in the poloidal direction, localized near the low-field side (LFS) midplane. Expelled particles from the LFS midplane were measured by using scrape-off layer Mach probes, and the heat flux to the divertor target was measured using a fast infrared TV camera. The time constant of the peak heat load was comparable to that of the enhancement of the plasma flow towards the divertor target. The normalized ELM energy loss by pedestal stored energy in JT-60U was found to be less than 10% of the pedestal stored energy. It shows weak dependence on the pedestal parameters such as electron collisionality, parallel ion loss time and the ratio of the pedestal density to the Greenwald density limit.

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Section: Collapse Phasesupporting

confidence: 84%

Fast dynamics of type I ELMs and transport of the ELM pulse in JT-60U

et al. 2004

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“…This large toroidal rotation is of course produced by the momentum input from tangential NBIs. However, whether the enhancement of the toroidal rotation contributes greatly to the increase in ion temperature [25] is yet to be found, whereas the relationship between the toroidal rotation and the density peaking is quite reasonable, as described later. In contrast, no large toroidal rotation is observed in the Ne discharges, although the central ion temperature reaches 4 keV.…”

Section: High-z Discharges With High Ion Temperaturementioning

confidence: 87%

Progress in Impurity-Related Physics Experiments in LHD

Morita

Dong

Goto

et al. 2010

Plasma and Fusion Research

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A variety of density profiles observed in the Large Helical Device (LHD) have suggested an interesting core impurity transport. The edge impurity transport in the ergodic layer formed by stochastic magnetic field lines with long connection length (10-2000 m) can also exhibit interesting phenomena in the competition of perpendicular and parallel transport. The LHD discharge is highly robust against impurity buildup, and operation is possible essentially up to the global power balance limit because current-driven instability does not principally exist. The LHD plasma has therefore provided information on many interesting physics issues closely related to impurities. Recent results of impurity-related physics experiments in the LHD are briefly reviewed. The specific contents presented here are (1) core impurity behavior with perpendicular transport, (2) edge impurity behavior with parallel transport, (3) high-Z discharges with high ion temperature, (4) impurity pellet injection with improved plasma performance, (5) impurity pellet ablation in the presence of energetic ions with high heat flux and (6) observation of magnetic dipole forbidden transitions for high-Z elements. A result from the Compact Helical System (CHS) is used only in the impurity pellet ablation study, because detailed data have not yet been obtained from the LHD. Finally, the results are summarized and future directions in these topics are noted.

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“…The beneficial effects of high triangularity in reaching high density and confinement in JET could possibly be linked to improved access of the plasma edge to second stability, as seen on other tokamaks, e.g. DIII-D [9]. A tradeoff has been observed between triangularity and heating power to reach high density and high confinement.…”

Section: High Density and High Confinement In Highly Triangular Plasmasmentioning

confidence: 99%

Towards the realization on JET of an integrated H-mode scenario for ITER

Ongena¹,

Monier‐Garbet

Suttrop

et al. 2003

Nucl. Fusion

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ELMy H-mode experiments at JET in 2000/mid-2002 have focused on discharges with normalized parameters for plasma density, energy confinement and beta similar to those of the ITER Q DT = 10 reference regime (n/n GW ∼ 0.85, H 98(y,2) ∼ 1, β N ∼ 1.8). ELMy H-mode plasmas have been realized reaching or even exceeding those parameters in steady-state conditions (up to ∼5 s or 12τ E) in a reproducible way and only limited by the duration of the additional heating phase. These results have been obtained (a) in highly triangular plasmas, by increasing the average a Researcher at NFSR Belgium. b Partners in the Trilateral Euregio Cluster (TEC). c See annex in IAEA 2002 J. Pamela IAEA-CN94/OV-1/1.4.

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Plasma confinement with a transport barrier

Cited by 29 publications

References 7 publications

Fast dynamics of type I ELMs and transport of the ELM pulse in JT-60U

Fast dynamics of type I ELMs and transport of the ELM pulse in JT-60U

Progress in Impurity-Related Physics Experiments in LHD

Towards the realization on JET of an integrated H-mode scenario for ITER

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