Refine your search:     
Report No.
 - 
Search Results: Records 1-15 displayed on this page of 15
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Observation of divertor and core radiation in JT-60U by means of bolometric imaging

Peterson, B. J.*; Konoshima, Shigeru; Parchamy, H.*; Kaneko, Masashi*; Omori, Toshimichi*; Seo, D. C.*; Ashikawa, Naoko*; Sukegawa, Atsuhiko; JT-60 Team

Journal of Nuclear Materials, 363-365, p.412 - 415, 2007/06

 Times Cited Count:12 Percentile:66.47(Materials Science, Multidisciplinary)

Diagnosis of the radiation from both the divertor and core plasma regions is a key issue for the study of impurities resulting from plasma-surface interaction in existing magnetic plasma confinement experiments and future fusion reactors. An infrared imaging video bolometer has been designed, fabricated and installed on the JT-60U tokamak. This diagnostic utilizes an IR camera to image the temperature change of a thin foil which is exposed to plasma radiation through an aperture resulting in an image of the incident plasma radiation absorbed by the foil. In the 2004-2005 experimental campaign intitial data was taken which was limited to 8-bit analog video data from ohmic and hydrogen neutral beam discharges due to inadequate shielding. The semitangential, wide-angle view of the plasma covers the entire poloidal cross-section and the divertor extending over 90 degrees toroidally. This preliminary data showed a strong radiation zone from the divertor that moved up into the core plasma as the discharge terminated in agreement with the data from the resistive bolometer arrays. For the current campaign we have upgraded the system by improving the shielding against neutrons, $$gamma$$ and magnetic field. This has enabled operation of the camera during high magnetic field and some high power deuterium neutral beam discharges. We also improved the triggering and data transmission system to acquire 14-bit digital data. This will allow processing of the IR camera data to produce images of the radiation brightness at the foil which can be viewed as a movie with a frame rate of 30 fps. This data is used to study the toroidal uniformity of the radiation from the divertor in JT-60U.

Journal Articles

ITER and plasma surface interaction issues in a fusion reactor

Shimomura, Yasuo

Journal of Nuclear Materials, 363-365, p.467 - 475, 2007/06

 Times Cited Count:29 Percentile:88.58(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Deuterium depth profiling in JT-60U tiles using the D($$^{3}$$He, p)$$^{4}$$He resonant nuclear reaction

Hayashi, Takao; Sugiyama, Kazuyoshi*; Krieger, K.*; Mayer, M.*; Alimov, V. Kh.*; Tanabe, Tetsuo*; Masaki, Kei; Miya, Naoyuki

Journal of Nuclear Materials, 363-365, p.904 - 909, 2007/06

 Times Cited Count:11 Percentile:63.76(Materials Science, Multidisciplinary)

The absolute concentrations and the depth profiles of deuterium in plasma-facing graphite tiles used in JT-60U were determined by means of the D($$^{3}$$He, p)$$^{4}$$He resonant nuclear reaction. The highest deuterium concentration was found at a plasma-facing surface near the outer pumping slot on the outer dome wing tile, where redeposited layers with thicknesses in the micron or submicron range were observed, indicating deuterium codepostion with carbon. In addition, a high flux of high energy deuterium originating from NBI is expected on the outer dome wing as well as on the dome top tile, and could have some contribution to this area of highest deuterium retention. The deuterium content integrated up to about 16 $$mu$$m was $$approx$$2.5$$times$$10$$^{22}$$ D/m$$^{2}$$. The depth profile has a broad peak in the atomic ratio of D/C$$approx$$0.05 at a depth of about 2.5 $$mu$$m. This is mainly because D retained in the top surface was replaced by H due to isotope exchange during H discharges, which were carried out to remove tritium from the plasma-facing wall before air ventilation. In erosion dominated areas such as the outer divertor tiles, the amount of deuterium was one order of magnitude lower than that on the outer dome wing tile. In the first wall area, the highest amount of deuterium with a content of $$approx$$1.0$$times$$10$$^{22}$$ D/m$$^{2}$$ was found in the upper region, nearest to the plasma. Again implantation of high energy deuterium due to NBI could have some contribution to the high deuterium retention.

Journal Articles

Study of highly ionized Xe spectra with 3s-3p and 3p-3d transitions in JT-60U reversed shear plasmas

Kubo, Hirotaka; Sasaki, Akira; Moribayashi, Kengo; Higashijima, Satoru; Takenaga, Hidenobu; Shimizu, Katsuhiro; Nakano, Tomohide; Whiteford, A.*; Sugie, Tatsuo

Journal of Nuclear Materials, 363-365, p.1441 - 1445, 2007/06

 Times Cited Count:6 Percentile:44.88(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Simulation of divertor pumping in JT-60U with SOLDOR/NEUT2D code

Kawashima, Hisato; Shimizu, Katsuhiro; Takizuka, Tomonori; Asakura, Nobuyuki; Takenaga, Hidenobu; Nakano, Tomohide; Sakurai, Shinji

Journal of Nuclear Materials, 363-365, p.786 - 790, 2007/06

 Times Cited Count:10 Percentile:60.87(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Modeling of dynamic response of SOL-divertor plasmas to an ELM crash

Hayashi, Nobuhiko; Takizuka, Tomonori; Hosokawa, Masanari*

Journal of Nuclear Materials, 363-365, p.1044 - 1049, 2007/06

 Times Cited Count:12 Percentile:66.47(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Understanding the SOL flow in L-mode plasma on divertor tokamaks, and its influence on the plasma transport

Asakura, Nobuyuki; ITPA SOL and Divertor Topical Group*

Journal of Nuclear Materials, 363-365, p.41 - 51, 2007/06

 Times Cited Count:84 Percentile:98.46(Materials Science, Multidisciplinary)

SOL mass transport along the magnetic field lines (SOL flow) is of direct relevance to divertor pumping and impurity screening properties. In this review, recent progresses in the SOL flow measurements and modellings in tokamak plasmas, and understanding of the effects on plasma and impurity transport will be summarized.

Journal Articles

Surface studies of tungsten erosion and deposition in JT-60U

Ueda, Yoshio*; Fukumoto, Masakatsu*; Nishikawa, Masahiro*; Tanabe, Tetsuo*; Miya, Naoyuki; Arai, Takashi; Masaki, Kei; Ishimoto, Yuki*; Tsuzuki, Kazuhiro*; Asakura, Nobuyuki

Journal of Nuclear Materials, 363-365, p.66 - 71, 2007/06

 Times Cited Count:9 Percentile:57.83(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

A New fast velocity-diffusion modelling for impurity transport in integrated edge plasma simulation

Shimizu, Katsuhiro; Takizuka, Tomonori; Kawashima, Hisato

Journal of Nuclear Materials, 363-365, p.426 - 431, 2007/06

 Times Cited Count:10 Percentile:60.87(Materials Science, Multidisciplinary)

For compatibility of high confinement core plasma with strong radiative divertor, it is necessary to establish the control method for impurity retention in the divertor region. We have been studying the impurity behavior in divertor plasmas with a simulation code, IMPMC. A conventional Monte-Carlo algorithm for scattering process in velocity space has a disadvantage that the impurity ions must be traced with a time step shorter than the slowing down time. The IMPMC code demands huge computational time in case of detached plasma. We have developed a new diffusion model using the analytical solution of Langevin equations. By the new diffusion model, we got a prospect of the self-consistent modeling of divertor plasmas and impurity transport, i.e. combining the SOLDOR/NEUT2D and the IMPMC Code. The unified code named SONIC clarifies the impurity transport in the MARFE plasma in consideration of kinetic effects. We carried out the simulation analysis for the JT-60U plasma at first with the IMPMC code. It was found that the radiation near the X-point during MARFE is caused dominantly by deeply penetrating carbons, which are dissociated from the methane (CH$$_{4}$$) chemically sputtered from the private region.

Journal Articles

Hydrogen isotopes retention in JT-60U

Hirohata, Yuko*; Tanabe, Tetsuo*; Oya, Yasuhisa*; Okuno, Kenji*; Masaki, Kei; Miya, Naoyuki; JT-60U Team

Journal of Nuclear Materials, 363-365, p.854 - 861, 2007/06

 Times Cited Count:11 Percentile:63.76(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Comparison of boronized wall in LHD and JT-60U

Ashikawa, Naoko*; Kizu, Kaname; Yagyu, Junichi; Nakahata, Toshihiko*; Nobuta, Yuji; Nishimura, Kiyohiko*; Yoshikawa, Akira*; Ishimoto, Yuki*; Oya, Yasuhisa*; Okuno, Kenji*; et al.

Journal of Nuclear Materials, 363-365, p.1352 - 1357, 2007/06

 Times Cited Count:9 Percentile:57.83(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Particle balance under global wall saturation in long-pulse discharges of JT-60U

Nakano, Tomohide; Asakura, Nobuyuki; Takenaga, Hidenobu; Kubo, Hirotaka; Shimizu, Katsuhiro; Kawashima, Hisato; JT-60 Team

Journal of Nuclear Materials, 363-365, p.1315 - 1322, 2007/06

 Times Cited Count:11 Percentile:63.76(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Ion beam analysis of H and D retention in the near surface layers of JT-60U plasma facing wall tiles

Sugiyama, Kazuyoshi*; Hayashi, Takao; Krieger, K.*; Mayer, M.*; Masaki, Kei; Miya, Naoyuki; Tanabe, Tetsuo*

Journal of Nuclear Materials, 363-365, p.949 - 954, 2007/06

 Times Cited Count:9 Percentile:57.83(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Effect of truncation of electron velocity distribution on release of dust particle from plasma-facing wall

Tomita, Yukihiro*; Smirnov, R.*; Nakamura, Hiroaki*; Zhu, S.*; Takizuka, Tomonori; Tskhakaya, D.*

Journal of Nuclear Materials, 363-365, p.264 - 269, 2007/06

 Times Cited Count:5 Percentile:39.35(Materials Science, Multidisciplinary)

In the study of dust behavior in plasma it is usually assumed that plasma particles are Maxwell distributed. If the dust is located on the conducting wall, the surrounding particle distribution can significantly differ from the Maxwellian. In this work we study the effect of truncation of electron velocity distribution on release conditions of a spherical dust particle from a plasma-facing wall. The truncation effect enlarges the electric field at the wall compared compared to the Maxwellian. The stronger electric field at the wall makes the released region smaller when the gravitational force is directed from the wall.

Oral presentation

Laser Raman analysis of plasma facing carbon tiles

Yoshida, Masashi*; Tanabe, Tetsuo*; Sugiyama, Kazuyoshi*; Masaki, Kei; Miya, Naoyuki; Philipps, V.*

no journal, , 

no abstracts in English

15 (Records 1-15 displayed on this page)
  • 1