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Journal Articles

Crystal structure and electron density distribution analyses of Nd$$_{x}$$Ce$$_{1-x}$$O$$_{2-delta}$$ for electrolyte by Rietveld/ maximum entropy method

Taguchi, Tomitsugu; Igawa, Naoki; Birumachi, Atsushi; Asaoka, Hidehito; Miwa, Shuhei; Osaka, Masahiko

e-Journal of Surface Science and Nanotechnology (Internet), 13, p.339 - 342, 2015/06

Rare-earth doped ceria exhibits both ionic and electronic conductions, and those ceria with higher ratio of ionic conduction against electronic conduction is used as a solid electrolyte for solid oxide fuel cells. The electron density distributions in crystals are closely related to the electron diffusing pathway which affects the electronic conduction. In this study, we investigated the electron density distribution of doped ceria as a function of the content of Nd$$_{2}$$O$$_{3}$$-dopant to deduce the ratio of the electronic to ionic conduction. The crystal structure was refined with the space group, ${it Fm}$-3${it m}$, which is the same as undoped ceria. Ce and Nd ions randomly occupied the 4${it a}$ site and O ion the 8${it c}$ site. The electron conduction pathway was distributed through the 4${it a}$-8${it c}$ and 8${it c}$-8${it c}$ sites. The relationship between crystal structural change and electron density distribution as a function of the content of Nd$$_{2}$$O$$_{3}$$ dopant will be discussed.

Journal Articles

Electron density behavior during fast termination phase of post-disruption runaway plasma

Kawano, Yasunori; Nakano, Tomohide; Asakura, Nobuyuki; Tamai, Hiroshi; Isayama, Akihiko; Kondoh, Takashi; Hatae, Takaki; Takenaga, Hidenobu; Ide, Shunsuke

Purazuma, Kaku Yugo Gakkai-Shi, 81(10), p.743 - 744, 2005/10

Electron density of post-disruption runaway plasmas in JT-60U has been measured by the tangential CO$$_{2}$$ laser interferometer. Increases in electron density after the first drop of runaway plasma current have been observed during a fast termination phase of the runaway plasma. At the second current drop, an increase in electron density with multiple spikes or oscillation with the period of 1 ms has been found. It is suggested that the increased electron density seems to take part in the shorter current decay time after the second current drop.

Journal Articles

Improvement of Thomson scattering diagnostics using stimulated-Brillouin-scattering-based phase conjugate mirrors

Hatae, Takaki; Nakatsuka, Masahiro*; Yoshida, Hidetsugu*

Purazuma, Kaku Yugo Gakkai-Shi, 80(10), p.870 - 882, 2004/10

A high performance phase conjugate mirror by stimulated Brillouin scattering (SBS-PCM) is applied to Thomson scattering diagnostics in JT-60U for the first time. To improve the measurement performance, two developments were performed with SBS-PCM. First, we developed a new optical design to provide a double-pass scattering scheme with SBS-PCM. A laser beam passing through the plasma is reflected by the SBS-PCM, and a reflected beam returned back through the same path as coming one by the phase conjugate effect, and passed through the plasma again. The double path Thomson scattering scheme demonstrated in JT-60U plasma that a factor of 1.6 increase of the scattered light in contrast with single-pass scattering. Second, an improvement of the output power of YAG laser system using the SBS-PCM was performed. As a result, average power was increased over 8 times in contrast with conventional system, and was achieved up to 368 W (7.4 J $$times$$ 50 Hz). A multi-pass Thomson scattering scheme is also proposed based on the results of double-pass scattering.

Journal Articles

Thermodynamics in density-functional theory and force theorems

Chihara, Junzo*; Yamagiwa, Mitsuru

Progress of Theoretical Physics, 111(3), p.339 - 359, 2004/03

 Times Cited Count:5 Percentile:37.3(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Application of diamond window for infrared laser diagnostics in a tokamak device

Kawano, Yasunori; Chiba, Shinichi; Inoue, Akira*

Review of Scientific Instruments, 75(1), p.279 - 280, 2004/01

 Times Cited Count:12 Percentile:53.69(Instruments & Instrumentation)

It has been successful to apply CVD diamond plate as the vacuum window for infrared CO$$_{2}$$ laser interferometry and polarimetry for electron density measurement in the JT-60U tokamak. In comparison with to use the conventional zinc-selenide windows, the Faraday rotation component at diamond windows was small as negligible. This resulted in the improvement of the Faraday rotation measurement for a tokamak plasma by polarimetry.

Journal Articles

Generation of radial electric field induced by collisionless internal kink mode with density gradient

Matsumoto, Taro; Tokuda, Shinji; Kishimoto, Yasuaki; Naito, Hiroshi*

Physics of Plasmas, 10(1), p.195 - 203, 2003/01

 Times Cited Count:5 Percentile:16.93(Physics, Fluids & Plasmas)

Effects of density gradient on the collisionless m=1 internal kink mode in a cylindrical tokamak plasma are studied by the gyro-kinetic particle simulations. When the density gradient is not large enough to change the full reconnection process, the phenomena after the full reconnection, such as the secondary reconnection and the evolution of the safety factor profile, are changed considerably due to the self-generated radial electric field, i.e. the m=0 mode. The growing mechanism is explained by the difference of $$Etimes B$$ drift motion between ions and electrons, which is caused by the fast parallel motion of electron. Once the radial electric field is triggered by the symmetrical flow induced by the m=1 mode, the m=0 mode grows up to the same level as the m=1 mode, and drives an $$Etimes B$$ plasma rotation in the ion diamagnetic direction, which breaks the symmetrical plasma flow induced by the m=1 mode. The density and current distributions, and minimum safety factor after the full reconnection, are found to be affected by the asymmetrical flow driven by the m=1 and m=0 modes.

JAEA Reports

Evaluation of hydrogen permeation of fuel cladding materials under low energy plasma

Ogawa, Hiroaki*; Kiuchi, Kiyoshi

JAERI-Research 2002-037, 48 Pages, 2002/12

JAERI-Research-2002-037.pdf:2.57MB

The difference in hydrogen permeation among candidate cladding materials such as 25Cr-35Ni stainless steel, Nb liner and reference materials such as 18Cr-8Ni SS, and Zr of Zircaloy base metal were evaluated by low energy plasma permeation simulated to hydrogen excited by heavy neutron irradiation. RF excitation source was arranged for the experimental apparatus in cooperating with temperature and bias control. Comparing with the thermodynamic gas driven permeation (GDP) in the same hydrogen pressure, the hydrogen permeation rate by the plasma driven permeation (PDP) was markedly accelerated at low to medium temperature range. The temperature dependency showed a knick at around 530K due to hydrogen-defect interactions. Comparing with Zr, Nb showed the high hydrogen solubility without the degradation by hydrate formation that is required to a getter material. The difference in PDP among candidates was analyzed with a new dissolution model for hydrogen.

Journal Articles

Gyro-kinetic particle simulation of m=1 internal kink mode in the presence of density gradient

Matsumoto, Taro; Tokuda, Shinji; Kishimoto, Yasuaki; Takizuka, Tomonori; Naito, Hiroshi*

Purazuma, Kaku Yugo Gakkai-Shi, 75(10), P. 1194, 1999/10

no abstracts in English

Journal Articles

Collisional effects on population inversion in optical-field-ionized plasmas

Sagisaka, Akito*; Nagashima, Keisuke; Yamagiwa, Mitsuru; Matoba, Toru; *

Journal of the Physical Society of Japan, 68(4), p.1221 - 1227, 1999/04

 Times Cited Count:2 Percentile:26.15(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Multilaser and high spatially resolved multipoint Thomson scattering system for the JT-60U tokamak

Yoshida, Hidetoshi; Naito, Osamu; Yamashita, Osamu; Kitamura, Shigeru; *; *; *; *; Hatae, Takaki; Nagashima, Akira; et al.

Review of Scientific Instruments, 70(1), p.751 - 754, 1999/01

 Times Cited Count:15 Percentile:68.26(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Complex behavior of internal collapse due to self-generated radial electric field

Matsumoto, Taro; Tokuda, Shinji; Kishimoto, Yasuaki; Takizuka, Tomonori; Naito, Hiroshi*

Journal of Plasma and Fusion Research SERIES, Vol.2, p.97 - 100, 1999/00

no abstracts in English

Journal Articles

ITER physics basis, 3; MHD stability, disruptional limits and disruptions

ITER Physics Expert Group on Disruptions, Plasma Control, and MHD

Nuclear Fusion, 39(12), p.2251 - 2389, 1999/00

no abstracts in English

Journal Articles

Study of intensity ratios of He I lines (668nm, 706nm and 728nm) for measurement of electron temperature and density in the JT-60U divertor plasma

Kubo, Hirotaka; *; Takenaga, Hidenobu; Kumagai, Akira*; Sugie, Tatsuo; Sakurai, Shinji; Asakura, Nobuyuki; Higashijima, Satoru; Sakasai, Akira

Purazuma, Kaku Yugo Gakkai-Shi, 75(8), p.945 - 951, 1999/00

no abstracts in English

Journal Articles

Fast plasma shutdown by killer pellet injection in JT-60U with reduced heat flux on the divertor plate and avoiding runaway electron generation

Yoshino, Ryuji; Kondoh, Takashi; Neyatani, Yuzuru; Itami, Kiyoshi; Kawano, Yasunori; Isei, Nobuaki

Plasma Physics and Controlled Fusion, 39(2), p.313 - 332, 1997/02

 Times Cited Count:99 Percentile:93.13(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

JT-60U Thomson scattering system with multiple ruby lasers and high spatial resolution for high electron temperature plasma measurement

Yoshida, Hidetoshi; Naito, Osamu; Yamashita, Osamu; Kitamura, Shigeru; Hatae, Takaki; Nagashima, Akira

JAERI-Research 96-061, 20 Pages, 1996/11

JAERI-Research-96-061.pdf:1.1MB

no abstracts in English

Journal Articles

Disruption amelioration experiments in JT-60U and JET

Yoshino, Ryuji; Neyatani, Yuzuru; Isei, Nobuaki; Koide, Yoshihiko; Kawano, Yasunori; A.Tanga*; Campbell, D. J.*; M.F.Johnson*; L.Rossi*

IAEA-CN-60/A5-8, 0, p.685 - 695, 1995/00

no abstracts in English

Journal Articles

Application of potential constants: Electronic chemical potentials of polyatomic molecules, VIII

; Suzuki, Kazuya

Spectrochimica Acta, Part A, 50(6), p.1057 - 1063, 1994/00

no abstracts in English

Journal Articles

Electronic chemical potentials of polyatomic molecules

Journal of Physical Chemistry, 97(9), p.1832 - 1834, 1993/00

 Times Cited Count:10 Percentile:41.34(Chemistry, Physical)

no abstracts in English

Journal Articles

Softening of Current quenches in JT-60U

Yoshino, Ryuji; Neyatani, Yuzuru; Hosogane, Nobuyuki; S.W.Wolfe*; Matsukawa, Makoto; Ninomiya, Hiromasa

Nuclear Fusion, 33(11), p.1599 - 1612, 1993/00

 Times Cited Count:34 Percentile:71.57(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Velocity distributions in high density gadolinium atomic beam produced with axial electron beam gun

Nishimura, Akihiko; Oba, Hironori; Shibata, Takemasa

Journal of Nuclear Science and Technology, 29(11), p.1054 - 1060, 1992/11

no abstracts in English

27 (Records 1-20 displayed on this page)