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Oya, Kaoru*; Inai, Kensuke*; Shimizu, Katsuhiro; Takizuka, Tomonori; Kawashima, Hisato; Hoshino, Kazuo; Hatayama, Akiyoshi*; Toma, Mitsunori*; Tomita, Yukihiro*; Kawamura, Gakushi*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 85(10), p.695 - 703, 2009/10
no abstracts in English
Oya, Kaoru*; Inai, Kensuke*; Kikuhara, Yasuyuki*; Nakano, Tomohide; Kawata, Jun*; Kawazome, Hayato*; Ueda, Yoshio*; Tanabe, Tetsuo*
Journal of Plasma and Fusion Research SERIES, Vol.8, p.419 - 424, 2009/09
Redeposition of C
H
and CH
chemically eroded from carbon walls is simulated by EDDY code incorporated with the reflection on a hydrogenated and amorphized carbon surface. The redeposition rate for heavy hydrocarbons is drastically decreased by introduction of the reflection. The redeposition patterns on the surface are enlarged by the reflection, but it is narrower for the heavy hydrocarbons than for CH. The photon emissions of C from CH (CH) decay faster than that of CH from CH in high-temperature (
10 eV) plasmas, which reproduces the difference of the decay of the CD and C light intensities observed in the vicinity of the outer diverter plates of JT-60U. For such temperatures, the inverse photon-efficiency, which is defined as the ratio of the number of the launching hydrocarbons to the photoemission events of CH and C, is in good agreement with the values observed in JT-60U experiments.
Hoshino, Kazuo; Toma, Mitsunori*; Furubayashi, Masahiko*; Hatayama, Akiyoshi*; Inai, Kensuke*; Oya, Kaoru*
Journal of Nuclear Materials, 390-391, p.168 - 171, 2009/06
Times Cited Count：4 Percentile：30.49(Materials Science, Multidisciplinary)The self-sputtering yield and the reflection yield are important for a prediction of the tungsten impurity content penetrating into the main plasma in future fusion reactors. These yields greatly depend on the incident angle of impurities to the plasma facing components. The IMPGYRO code is applied to the analysis of the angle distribution of incident impurities and the effect of the incident angle and energy on the sputtering and reflection yields. The incident angle distribution is divided into several peaks corresponding to charge states. This is caused by the different acceleration for each charge state by the sheath. In the attached plasma case, the sheath increases the self-sputtering yield. This is due to the change of the incident angle by the sheath rather than the change of the incident energy. On the other hand, in the detached plasma case, the significant effects of the sheath on the sputtering yield and the reflection yield is not seen.
Shimizu, Katsuhiro; Takizuka, Tomonori; Oya, Kaoru*; Inai, Kensuke*; Nakano, Tomohide; Takayama, Arimichi*; Kawashima, Hisato; Hoshino, Kazuo
Nuclear Fusion, 49(6), p.065028_1 - 065028_9, 2009/06
Times Cited Count：60 Percentile：89.24(Physics, Fluids & Plasmas)The self-consistent coupling of a Monte Carlo (MC) impurity code IMPMC to a divertor code SOLDOR/NEUT2D has been succeeded. MC modelling is required for impurity transport in order to take into account the kinetic effect and the complex dissociation processes of hydrocarbons. The integrated divertor code SONIC enables us to investigate the details of impurity transport including erosion/redeposition processes on the divertor plates by further coupling of an MC code EDDY. The dynamic evolution of X-point MARFE observed in JT-60U is investigated. The simulation results indicate that the hydrocarbons sputtered from the dome contribute to the enhanced radiation near the X-point. The kinetic effect of thermal force on the He transport is investigated for JT-60SA detached plasmas. Without the recycling, the kinetic effect improves the helium compression, compared with the conventional (fluid) evaluation. This effect is, however, masked by the recycling at the divertor targets.
Shimizu, Katsuhiro; Takizuka, Tomonori; Oya, Kaoru*; Inai, Kensuke*; Nakano, Tomohide; Takayama, Arimichi*; Kawashima, Hisato; Hoshino, Kazuo
Proceedings of 22nd IAEA Fusion Energy Conference (FEC 2008) (CD-ROM), 12 Pages, 2008/10
The self-consistent coupling of an MC impurity code IMPMC to a divertor code SOLDOR/NEUT2D is succeeded by overcoming the intrinsic problems of Monte Carlo (MC) modelling for impurity transport. MC modelling for impurity transport is required in order to take into account the kinetic effect and the complex dissociation processes of hydrocarbons. The integrated divertor code SONIC enables us to investigate the details of impurity transport including erosion/redeposition processes on the divertor plates by further coupling of an MC code EDDY. The dynamic evolution of X-point MARFE observed in JT-60U is investigated. The simulation results indicate that the hydrocarbons sputtered from the dome contribute directly to the enhanced radiation near the X-point. Without the recycling, the kinetic effect of the thermal force improves the helium compression, compared with the conventional (fluid) evaluation. This effect is, however, masked by the recycling at the divertor targets.
Oya, Kaoru*; Tanabe, Tetsuo*; Takenaga, Hidenobu; Inai, Kensuke*
no journal, ,
Dynamic simulation results of erosion and redeposition on plasma facing materials were reported. In JT-60U W-shaped divertor, erosion was dominant on the outer divertor plate, whereas deposition was dominant on the inner plate. The erosion and redeposition patterns on the plates were calculated using the EDDY code, which treats transport of impurities released from the plates in the plasma and dynamic material mixing processes. Forthermore, energy-dependent reflection and dissociation of hydrocarbons on the surface was employed in addition to a constant sticking coefficient on the plate. Hydrocarbons released from the outer divertor plate were immediately ionized when entering the plasma and were redeposited near the release position. But they were subjected to re-erosion, resulting in small effective sticking. On the whole, most area of the outer divetor plate was eroded. In contrast, the inner divertor plate was dominated by deposition due to lower plasma temperature. These results agreed with the experimental observations. Simulations for the twin test limiter experiments in TEXTOR, hydrocarbon redeposition in castellated surfaces and molecular dynamics of ion-solid interactions were also reported.
Shimizu, Katsuhiro; Takizuka, Tomonori; Oya, Kaoru*; Inai, Kensuke*; Nakano, Tomohide; Takayama, Arimichi*; Kawashima, Hisato; Hoshino, Kazuo
no journal, ,
An integrated divertor simulation code SONIC has been developed. The self-consistent coupling of a Monte Carlo (MC) impurity code IMPMC to a divertor code SOLDOR/NEUT2D is succeeded by overcoming the intrinsic problems of MC modelling for impurity transport. MC modelling for impurity transport is required in order to take into account the kinetic effect and the complex dissociation processes of hydrocarbons. The dynamic evolution of X-point MARFE observed in JT-60U is investigated. The simulation results indicate that the hydrocarbons sputtered from the dome contribute to the enhanced radiation near the X-point. Without the recycling, the kinetic effect of the thermal force improves the helium compression, compared with the conventional (fluid) evaluation. This effect is, however, masked by the recycling at the divertor targets.
