The effects of drifts and associated flows and currents on the width of the parallel heat flux channel (λq) in the tokamak scrape-off layer (SOL) are analyzed using the SOLPS-ITER 2D fluid transport ...code. Motivation is supplied by Goldston’s heuristic drift (HD) model for λq, which yields the same approximately inverse poloidal magnetic field dependence seen in multi-machine regression. The analysis, focusing on a DIII-D H-mode discharge, reveals HD-like features, including comparable density and temperature fall-off lengths in the SOL, and up-down ion pressure asymmetry that allows net cross-separatrix ion magnetic drift flux to exceed net anomalous ion flux. In experimentally relevant high-recycling cases, scans of both toroidal and poloidal magnetic field (Btor and Bpol) are conducted, showing minimal λq dependence on either component of the field. Insensitivity to Btor is expected, and suggests that SOLPS-ITER is effectively capturing some aspects of HD physics. Absence of λq dependence on Bpol, however, is inconsistent with both the HD model and experimental results. As a result, the inconsistency is attributed to strong variation in the parallel Mach number, which violates one of the premises of the HD model.
New Grad's-Zhdanov module is implemented in the SOLPS-ITER code and applied to ITER impurity transport simulations. Significant difference appears in the helium transport due to improved parallel ...kinetic coefficients. As a result 30\% decrease of the separatrix-averaged helium relative concentration is observed for the constant helium source and pumping speed. Change of the impurity behaviour is discussed. For the neon changes are less pronounced. For the first time the ion distribution functions are studied in the ITER Scrape-off layer conditions to reveal the origin of the kinetic coefficient improvements and theory limitations.
Electron temperature and density spatial distribution dynamics on the Globus-M (R =0.36 m, a=0.24 m, B =0.4 T, I= 0.2 MA) spherical tokamak was investigated during the NBI heating. The key tool of ...this research was the upgraded Thomson scattering diagnostics with variable intervals between probing pulses (20 pulses in total). The scattering points were placed along the major plasma radius from the inner to the outer plasma border (10 points in total). Simulation of the electron transport in the L and H-mode, based on experimentally measured ne(R) Te(R) profiles was carried out using the code ASTRA for the OH and NBI dischargers.
Kinetics of Dissolution of Glassy Fertilizers Karapetyan, K. G.; Senichenkov, V. A.; Zenin, G. S. ...
Russian journal of applied chemistry,
09/2005, Volume:
78, Issue:
9
Journal Article
Peer reviewed
Slowly soluble phosphate glasses are a promising material for new environmentally safe fertilizers. The kinetics of the dissolution of phosphate glasses used for the development of fertilizers was ...studied.
Modeling of the pellet ablation cloud evolution with account of the ∇B induced drift motion is performed. The model includes acceleration in the low-field-side direction, Alfven conductivity of the ...background plasma, compensation of ∇B currents in different parts of the cloud during its propagation along the magnetic field, cloud heating, expansion and ionization and simulation of the pellet ablation rate in a self-consistent manner. The time evolution of density and temperature profiles and the mass deposition after the pellet injection are calculated. The size of neutral part of the cloud, the characteristic values of cloud density and temperature far from the pellet and the fuelling efficiency are in a reasonable agreement with those observed in experiments on ASDEX-Upgrade tokamak.
Modeling of the pellet ablation cloud evolution with account of the DeltaB induced drift motion is performed. The model includes acceleration in the low-field-side direction, Alfven conductivity of ...the background plasma, compensation of DeltaB currents in different parts of the cloud during its propagation along the magnetic field, cloud heating, expansion and ionization and simulation of the pellet ablation rate in a self-consistent manner. The time evolution of density and temperature profiles and the mass deposition after the pellet injection are calculated. The size of neutral part of the cloud, the characteristic values of cloud density and temperature far from the pellet and the fuelling efficiency are in a reasonable agreement with those observed in experiments on ASDEX-Upgrade tokamak.
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