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[en] The analytical theories of the geodesic acoustic mode (GAM) are reviewed in the small and large orbit drift width limit respectively. Different physics pictures in these two limits are displayed. These analytical methods are applied to investigate the plasma shaping effect on the frequency and collisionless damping rate of the GAM. (author)

[en] The graphite and carbon fibre composites used as plasma facing components in fusion devices are composed of graphitic crystallites, connected by intercrystalline voids. The porous structure gives rise to great complexity to understand the hydrogen transport behaviour in graphite. In this work dynamic Monte Carlo simulations are carried out to understand the dependence of the hydrogen retention, re-emission, and thermal desorption on the void fraction of graphite. The results show that the void fraction plays an important role in hydrogen retention and release behaviour. (author)

[en] The zonal flow eigenmodes in a tokamak plasma with dominantly poloidal mean flows are theoretically investigated, using different state equations. It is found that the frequencies of both the geodesic acoustic mode and the sound wave increase with respect to the poloidal Mach number. In contrast to the pure standing wave form in static plasmas, the density perturbations consist of a standing wave superimposed with a small amplitude traveling wave in the poloidally rotating plasma. A finite frequency for usual low frequency zonal flow is acquired proportional to the poloidal Mach number using the adiabatic perturbation, while for isothermal assumption of temperature, the frequency remains to be 0. (author)

[en] Using the typical edge plasma parameters of the Experimental Advanced Superconducting Tokamak (EAST), the erosion and deposition behavior of the SiC coating were calculated with the modified Erosion and Deposition based on DYnamic model (EDDY code). Compared to those on the non-doped graphite, it's found that less deposition and erosion occurred on the SiC coating. Further benchmarking experiments on EAST have been planed. (author)

[en] In order to describe time evolution of tokamak core plasmas, the integrated tokamak modeling code, TASK, has been developed. It is composed of analyses of equilibrium, transport, wave physics, and momentum distribution function, and interface to couple them with each other. The features of each component are described and typical simulation results for ITER are presented. The kinetic integrated modeling under development is also mentioned. (author)

[en] The edge plasma transport code SOLPS5.0 is used for modelling edge plasmas on JT-60U tokamak. The modelling results are matched to the experimental measurement of the edge plasmas in L-mode and H-mode shots and the radial transport coefficients at the edge have been obtained by fitting the experimental measurement with the results of the transport code. (author)

[en] In order to investigate the power and particle control with divertor system of fusion reactors, numerical simulations have been widely carried out. Fluid codes require further improvement of physics modeling for edge plasmas. The full particle simulation is powerful to study fundamental physics of open-field SOL-divertor plasmas as well as of the whole tokamak plasma including SOL-divertor region. PARASOL code with PIC method and binary collision model has been developed in JAERI and JAEA. Simulations with PARASOL code have been carried out for the above purpose. The one-dimensional (1D) version of PARASOL was applied to investigate the Bohm criterion, the supersonic flow, the SOL heat conduction, and so on. The ELM heat propagation was studied with the 1D-dynamic PARASOL. The two-dimensional version of PARASOL for the whole tokamak plasma with SOL-divertor region was useful to simulate the SOL flow pattern, the electric field formation etc. Based on PARASOL simulation results, physics modeling for the fluid simulation has been constructed. (author)

[en] Edge impurity transport has been investigated in the stochastic layer of LHD and the scrape-off layer (SOL) of HL-2A, as a comparative analysis based on carbon emission profile measurement and three-dimensional edge transport simulation. The 3D simulation predicts impurity screening effect in the both devices, but with different behavior against collisionality and the impurity source location. The difference is attributed to topological effects of the field lines in the stochastic layer and X-point poloidal divertor SOL. The carbon emission (CIV) profile in the stochastic layer of LHD shows clear signature of impurity movement towards downstream at high density range, in reasonable agreement with the 3D code simulation predicting impurity screening. Comparison of CIV profile measurements in HL-2A with the modelling implies that there exists either additional impurity source than the divertor sputtering or another screening effect at the upstream (X-point) such as strong poloidal flow formation, which is not taken into account in the present model. (author)

[en] The castellated structure will be used at the divertor region to maintain the thermo-mechanical stability in ITER. Hydrocarbons generated by chemical erosion depositing in the gaps between the divertor tiles can cause tritium retention. In order to investigate the deposition behavior of impurities, we carry out simulations to study impurities transport, collisions and deposition in the toroidal gaps of shaped cells. The simulation results on several scenarios with different magnetic field configurations, plasma temperatures and densities show that they have a significant influence on the H/C ratio of deposited species on the bottom of the toroidal gaps: The magnetic field with a smaller incident angle can reduce the H/C ratio of deposited species noticeably; when the plasma density exceeds a certain value, the H content in deposited impurities on the bottom of the toroidal gaps becomes negligible. (author)