Fluid-particle hybrid simulation on the transports of plasma, recycling neutrals, and carbon impurities in the Korea Superconducting Tokamak Advanced Research divertor region

Kim, Deok-Kyu; Hong, Sang Hee

doi:10.1063/1.1914807

Cited by 6 publications

(6 citation statements)

References 32 publications

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“…where the diffusion coefficients D and D r represent κ or η in the governing equations, respectively. The parallel fluxes through the northern and southern cell faces for equation (14) are not taken into consideration because both cell faces coincide with the magnetic flux surfaces. Likewise, the radial fluxes through the eastern and western cell faces in equation ( 15) are neglected in the computation based on the orthogonal grid.…”

Section: Numerical Schemesmentioning

confidence: 99%

“…To avoid a decoupling problem between the density and the parallel velocity, the Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm for a compressible flow is used. This is one of the most widely used numerical schemes for convection-conduction problems [12][13][14].…”

Section: Numerical Schemesmentioning

confidence: 99%

“…Although the kinetic effects probably play some roles in the formation and collapse of the edge transport barrier (ETB), the kinetic model is still too computationally expensive in the currently available computing environments to analyze the edge plasma completely with a real geometry. Therefore, the fluid model is used with some kinetic corrections considering some physics indicated by the kinetic model, such as the flux-limited condition [14]. In addition, we can use the simple diffusion equation for neutrals and this simple model is adequate for solving the time evolution problem, although it could make some uncertainty to the numerical results.…”

Section: Simulation Conditions For Type-i Elms In Kstarmentioning

confidence: 99%

“…This alternative assumption can be justified from figure 8, which shows that the edge-pedestal pressure gradient is correlated linearly with the plasma pressure at the center of the pedestal during the pedestal build-up process. The initial guess in the transport simulation is obtained from the outputs of the stationary transport simulation for the KSTAR baseline operation with 8.0 MW of additional heating power [14,20]. The additional heating power and other input parameters are prescribed by arbitrarily taking into account the feasibility of the KSTAR operation as well as the computational stability while running the code.…”

Section: Simulation Conditions For Type-i Elms In Kstarmentioning

confidence: 99%

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Simulation of edge-divertor plasma transport for high-performance operation in KSTAR

Han

Kim

Park

et al. 2011

Plasma Phys. Control. Fusion

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The edge-divertor plasma transport responding to type-I edge localized modes (ELMs) in a hybrid scenario and a conventional H-mode operation of the KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak is simulated using a newly developed two-dimensional fluid code named 'EPST', which can be used in time-dependent analyses of the edge-private flux-scrape-off layer region. It is verified through a benchmark test with the B2.5 code for a double-null configuration of the KSTAR tokamak. In this simulation, the KSTAR operation modes are distinguished by their β N values and the threshold pedestal heights for ELM triggering. Type-I ELMs are simulated under the ELM triggering condition by an ad hoc method of time-periodic changes in the transport coefficients in the near-separatrix region. As a result of numerical simulation, the overall distributions of plasma properties responding to the ELM bursts appear to be the same in the edge-divertor region regardless of their β N . However, the increased ballooning limit in the higher β N case makes the ELM frequency become lower, while it makes the maximum heat flux on the divertor plate higher compared with the lower β N case.

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Section: Numerical Schemesmentioning

confidence: 99%

Section: Numerical Schemesmentioning

confidence: 99%

Section: Simulation Conditions For Type-i Elms In Kstarmentioning

confidence: 99%

Section: Simulation Conditions For Type-i Elms In Kstarmentioning

confidence: 99%

See 2 more Smart Citations

Simulation of edge-divertor plasma transport for high-performance operation in KSTAR

Han

Kim

Park

et al. 2011

Plasma Phys. Control. Fusion

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“…For example, laboratory plasmas producing strong fluxes of hydrogen ions are used to mimic conditions encountered in Scrape-off-layer (SOL) of fusion plasma devices (cold region). [4][5][6][7] This enabled investigating the interaction between high deuterium ion flux and the divertor material. [8][9][10][11] Such laboratory "PSI simulators" have already been used for carbon and tungsten material studies.…”

Section: Introductionmentioning

confidence: 99%

Qualification of uniform large area multidipolar ECR hydrogen plasma

Colina-Delacqua¹,

Rédolfi²,

Ouaras

et al. 2022

Physics of Plasmas

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The design and characterization of a multi-dipolar microwave electron cyclotron resonance (ECR) hydrogen plasma reactor are presented. In this configuration, 16 ECR sources are disposed uniformly along the azimuthal direction at a constant distance from the center of a cylindrical reactor. Several plasma diagnostics have been used to determine key parameters such as neutral species temperature; electron density and temperature; and H+, H2+, and H3+ ion energy distributions. The experimental characterization is supported by electromagnetic and magnetostatic field simulations as well as Particle In-Cell Monte Carlo Collisions simulations to analyze the observed ion energy distribution functions. Especially, we show that both electron density and temperature are spatially uniform, i.e., 1011 cm−3 and 3 eV, respectively. This plasma enables generating ion flux and energy in the ranges 1019–1022 ions m−2 s−1 and few keVs, respectively. The H2+ ion distribution function shows two populations which were attributed to surface effects. These features make this reactor particularly suitable for studying hydrogen plasma surface interaction under controlled conditions.

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On mechanisms of impurity leakage and retention in the tokamak divertor

Senichenkov

Kaveeva

Sytova

et al. 2019

Plasma Phys. Control. Fusion

119

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Impurity seeding into a tokamak divertor for radiative cooling is considered as a tool for achieving detached/semi-detached regimes required to meet the condition of acceptable heat loads on divertor plates. Experiments aimed at searching of the operational window with a significant reduction of poloidal heat fluxes due to the impurity radiation and without the decreasing of confinement are performed on many tokamaks. Critical issue in these experiments is which fraction of impurities is retained in the divertor region and which is extracted upstream to the scrape-off layer (SOL). In the present paper a physical mechanism of impurity transport from a divertor towards upstream and back to the divertor is analyzed. It is demonstrated that the widespread concept that the impurity leaks if the parallel thermal force exceeds the friction due to main ions and retains otherwise-is not correct. In contrast, the impurity leaks if it crosses the stagnation point of impurity ion poloidal velocity profile before the ionization, and retains if it ionizes closer to the target than the location of that stagnation point. Thus the leakage efficiency depends on the relative spatial positions of the impurity atom ionization source and the stagnation point of the impurity ion poloidal velocity profile. The impurity ion poloidal velocity is a sum of poloidal projection of its parallel velocity and the E × B drift velocity, where the former should be defined from the parallel impurity force balance equation. It is demonstrated that the solution of this equation may be approximated by the balance of friction and thermal forces in all regimes, while other terms are smaller. This allows for expressing the impurity parallel velocity through the main ion one and makes the distribution of the parallel (poloidal) fluxes of the main ions, including Pfirsch-Schlüter (PS) fluxes and E × B drift fluxes, to be an important element of the impurity transport. It is shown that impurity distribution in the edge plasma is rather sensitive to the value of the impurity ion ionization potential. This analysis is supported by the simulation results obtained for the ASDEX Upgrade tokamak with various seeding rates of N and Ne with the SOLPS-ITER code. The importance of inclusion of self-consistent drift flows is demonstrated by the comparison to result of corresponding simulations with drifts turned off.

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Fluid-particle hybrid simulation on the transports of plasma, recycling neutrals, and carbon impurities in the Korea Superconducting Tokamak Advanced Research divertor region

Cited by 6 publications

References 32 publications

Simulation of edge-divertor plasma transport for high-performance operation in KSTAR

Simulation of edge-divertor plasma transport for high-performance operation in KSTAR

Qualification of uniform large area multidipolar ECR hydrogen plasma

On mechanisms of impurity leakage and retention in the tokamak divertor

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