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Title: Heat and Particle Control in JT-60U

Abstract

Heat and particle control has been studied under the reactor-relevant high-power heating in the large tokamak of JT-60U with an open divertor and progressively a W-shaped pumped divertor. Heat and particle control is crucial for reduction in heat load onto the divertor plates, control of density in the main plasma, effective exhaust of helium ash, and reduction in impurity contamination. For the reduction of heat load, radiative divertor concept was developed based on understanding of heat and particle transport in scrape-off layer and divertor plasmas, which contributed to establishment of divertor concept in ITER. With argon injection, the total radiation loss power reached up to 80% of the net heating power with high confinement of HH{sub y2} {approx} 1, where HH{sub y2} is a confinement enhancement factor over the IPB98(y,2) ELMy H-mode scaling, at high density of 80% of the Greenwald density in the ELMy H-mode plasma. For the density control, the dependence of particle confinement on plasma parameters was systematically studied with two confinement times for center- and edge-fueled particles, which enabled discussion of density controllability. Core fueling using a high-field-side pellet injection extended the operation range of high confinement (HH{sub y2} {approx} 1) from 60 to 70% ofmore » the Greenwald density in the high {beta}{sub p} ELMy H-mode plasma. Efficient helium ash exhaust of {tau}{sub He}*/{tau}{sub E} = 2.8 was demonstrated in the ELMy H-mode plasma with the pumping from the private flux region, which is the same pumping geometry as that in ITER design. Reduction in Z{sub eff} by puff-and-pump scheme was demonstrated, and chemical sputtering yields were estimated with the consideration of not only methane but also heavier hydrocarbons. Their sputtering yields showed strong dependence on the wall temperature and weak dependence on the particle flux. The measured profiles of C II and C IV line intensities were well reproduced by the Monte Carlo impurity transport simulation code (IMPMC code). The estimation of sputtering yields and development of the simulation code enabled reliable predictions for impurity behavior in a fusion reactor.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1]
  1. Japan Atomic Energy Research Institute (Japan)
Publication Date:
OSTI Identifier:
20845856
Resource Type:
Journal Article
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 42; Journal Issue: 2,3; Other Information: Copyright (c) 2006 American Nuclear Society (ANS), United States, All rights reserved. http://epubs.ans.org/; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1536-1055
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ARGON; COMPUTERIZED SIMULATION; CONTROL; DESIGN; DIVERTORS; EDGE LOCALIZED MODES; H-MODE PLASMA CONFINEMENT; HEATING LOAD; HELIUM ASH; ITER TOKAMAK; JT-60U TOKAMAK; METHANE; MONTE CARLO METHOD; OPERATION; PELLET INJECTION; PLASMA; PLASMA IMPURITIES; PLASMA SCRAPE-OFF LAYER; PLASMA SIMULATION; SPUTTERING

Citation Formats

Takenaga, H, Kubo, H, Higashijima, S, Asakura, N, Sugie, T, Konoshima, S, Shimizu, K, Nakano, T, Itami, K, Sakasai, A, Tamai, H, Sakurai, S, Miura, Y, Hosogane, N, and Shimada, M. Heat and Particle Control in JT-60U. United States: N. p., 2002. Web.
Takenaga, H, Kubo, H, Higashijima, S, Asakura, N, Sugie, T, Konoshima, S, Shimizu, K, Nakano, T, Itami, K, Sakasai, A, Tamai, H, Sakurai, S, Miura, Y, Hosogane, N, & Shimada, M. Heat and Particle Control in JT-60U. United States.
Takenaga, H, Kubo, H, Higashijima, S, Asakura, N, Sugie, T, Konoshima, S, Shimizu, K, Nakano, T, Itami, K, Sakasai, A, Tamai, H, Sakurai, S, Miura, Y, Hosogane, N, and Shimada, M. Sun . "Heat and Particle Control in JT-60U". United States.
@article{osti_20845856,
title = {Heat and Particle Control in JT-60U},
author = {Takenaga, H and Kubo, H and Higashijima, S and Asakura, N and Sugie, T and Konoshima, S and Shimizu, K and Nakano, T and Itami, K and Sakasai, A and Tamai, H and Sakurai, S and Miura, Y and Hosogane, N and Shimada, M},
abstractNote = {Heat and particle control has been studied under the reactor-relevant high-power heating in the large tokamak of JT-60U with an open divertor and progressively a W-shaped pumped divertor. Heat and particle control is crucial for reduction in heat load onto the divertor plates, control of density in the main plasma, effective exhaust of helium ash, and reduction in impurity contamination. For the reduction of heat load, radiative divertor concept was developed based on understanding of heat and particle transport in scrape-off layer and divertor plasmas, which contributed to establishment of divertor concept in ITER. With argon injection, the total radiation loss power reached up to 80% of the net heating power with high confinement of HH{sub y2} {approx} 1, where HH{sub y2} is a confinement enhancement factor over the IPB98(y,2) ELMy H-mode scaling, at high density of 80% of the Greenwald density in the ELMy H-mode plasma. For the density control, the dependence of particle confinement on plasma parameters was systematically studied with two confinement times for center- and edge-fueled particles, which enabled discussion of density controllability. Core fueling using a high-field-side pellet injection extended the operation range of high confinement (HH{sub y2} {approx} 1) from 60 to 70% of the Greenwald density in the high {beta}{sub p} ELMy H-mode plasma. Efficient helium ash exhaust of {tau}{sub He}*/{tau}{sub E} = 2.8 was demonstrated in the ELMy H-mode plasma with the pumping from the private flux region, which is the same pumping geometry as that in ITER design. Reduction in Z{sub eff} by puff-and-pump scheme was demonstrated, and chemical sputtering yields were estimated with the consideration of not only methane but also heavier hydrocarbons. Their sputtering yields showed strong dependence on the wall temperature and weak dependence on the particle flux. The measured profiles of C II and C IV line intensities were well reproduced by the Monte Carlo impurity transport simulation code (IMPMC code). The estimation of sputtering yields and development of the simulation code enabled reliable predictions for impurity behavior in a fusion reactor.},
doi = {},
journal = {Fusion Science and Technology},
issn = {1536-1055},
number = 2,3,
volume = 42,
place = {United States},
year = {2002},
month = {9}
}