Simulation of neutral gas flow in the JET sub-divertor

Varoutis, S.; Gleason-Gonzalez, C.; Moulton, D.; Kruezi, U.; Groth, M.; Day, Christian; Wiesen, S.; Harting, D.

doi:10.1016/j.fusengdes.2017.05.108

Cited by 26 publications

(19 citation statements)

References 26 publications

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“…To further strengthen this conclusion, figure 11 From the modelling point of view, results based on EDGE2D-EIRENE simulations applied to L-mode JET-ILW plasmas are qualitatively consistent with this conclusion [107,121,122].…”

Section: Separatrix Density and Its Correlation With The Pedestal Prementioning

confidence: 73%

“…These lead to an increase of the neutral pressure which is experimentally seen an increase in the separatrix density. This link is based on the experimental results discussed in section 5.2 and on EDGE2D-EIRENE simulations of L-mode plasmas[107,118,121,122] and it is rather reasonable. The increase of ne sep leads to the outward shift of the pedestal density.This link is based on the experimental results discussed in section 5.4 and it will require an in depth investigation with SOL modelling.…”

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confidence: 97%

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Pedestal structure, stability and scalings in JET-ILW: the EUROfusion JET-ILW pedestal database

et al. 2020

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The EUROfusion JET-ILW pedestal database is described, with emphasis on three main issues. First, the technical aspects are introduced, including a description of the data selection, the datasets, the diagnostics used, the experimental and theoretical methods implemented and the main definitions. Second, the JET-ILW pedestal structure and stability are described. In particular, the work describes the links between the engineering parameters (power, gas and divertor configuration) and the disagreement with the peeling-ballooning (PB) model implemented with ideal MHD equations. Specifically, the work clarifies why the JET-ILW pedestal tends to be far from the PB boundary at high gas and high power, showing that a universal threshold in power and gas cannot be found but that the relative shift (the distance between the position of the pedestal density and of the pedestal temperature) plays a key role. These links are then used to achieve an empirical explanation of the behavior of the JET-ILW pedestal pressure with gas, power and divertor configuration. Third, the pedestal database is used to revise the scaling law of the pedestal stored energy. The work shows a reasonable agreement with the earlier Cordey scaling in terms of plasma current and triangularity dependence, but highlights some differences in terms of power and isotope mass dependence.

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Section: Separatrix Density and Its Correlation With The Pedestal Prementioning

confidence: 73%

mentioning

confidence: 97%

Pedestal structure, stability and scalings in JET-ILW: the EUROfusion JET-ILW pedestal database

et al. 2020

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“…Monte Carlo calculations with realistic collision operators between Ar, Ne and D 2 and a realistic 3D divertor / pump chamber geometry would be highly desirable for a first-principle based description of impurity pumping [52]. Wall storage of Ne and Ar has been taken into account by a simple wall model.…”

Section: Integration With Divertor Detachment: Impurity Divertor Enri...mentioning

confidence: 99%

Developments towards an ELM-free pedestal radiative cooling scenario using noble gas seeding in ASDEX Upgrade

et al. 2020

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Integrated edge-localized-mode (ELM)-free or small ELM scenarios for the demonstration fusion power plant (DEMO) are investigated in ASDEX Upgrade using argon seeding for radiative power removal mainly in the pedestal region. An important aspect is the modification of the electron pressure in the pedestal by the additional radiative power losses. Full ELM suppression could be achieved in a no-ELM H-mode scenario featuring an edge electromagnetic quasicoherent mode up to a heating power of 5 MW, where argon radiation allowed the extension of the heating power operational space. At higher powers up to 12 MW (reaching the beta limit), ELMs of reduced size prevail and detachment is obtained by the argon seeding. Control of the position of a radiating zone localized inside the X-point was found to be favorable compared to the control of the separatrix power for low P s e p / P h e a t . Integration of pedestal cooling with Ar and ELM suppression by resonant magnetic perturbations (RMP) allowed an increase of the core radiation and a partial recovery of normalized confinement to H98 = 1. This favorable behavior is finally limited by the loss of the RMP density pump-out effect, followed by an ELM-free H-mode phase and re-occurrence of ELMs. For an active tailoring of the pedestal pressure profile, precise knowledge of the radiation profile is required. Modeling of the argon radiation profile with the STRAHL code showed good agreement with bolometry only if charge exchange of neutral deuterium with argon ions was taken into account, highlighting the importance of the neutral density in the pedestal region. In view of best integration of a no-ELM scenario with divertor detachment and high heating power, the divertor compression and enrichment of argon and neon were compared using dynamic gas puff experiments. Argon shows more than a factor of 3 higher divertor enrichment compared to neon, but the absolute values decrease with higher neutral deuterium pressure.

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“…The solution of the Boltzmann kinetic equation for neutrals can be obtained via different methods. The direct simulation Monte Carlo method (DSMC) approach [14] statistically mimics the behavior of real neutrals by tracking a group of model particles. Neutral transport can also be given by solving the Boltzmann equation with a nonlinear BGK approximation.…”

Section: Introductionmentioning

confidence: 99%

Simulation of helium supersonic molecular beam injection in tokamak plasma*

Wu¹,

Wang²,

Li³

et al. 2020

Chinese Phys. B

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To study helium (He) supersonic molecular beam injection (SMBI) into H-mode tokamak plasma, a simplified multicomponent-plasma model under the assumption of quasi-neutral condition is developed and implemented in the frame of BOUT ++. The simulation results show that He species propagate inwards after He SMBI, and are deposited at the bottom of the pedestal due to intensive ionization and weak spreading speed. It is found that almost all injected helium particles strip off all the bounded electrons. He species interact intensively with background plasma along the injection path during He SMBI, making deuterium ion density profile drop at the He-deposited location and resulting in a large electron temperature decreasing, but deuterium ion temperature decreasing a little at the top of the pedestal.

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Simulation of neutral gas flow in the JET sub-divertor

Cited by 26 publications

References 26 publications

Pedestal structure, stability and scalings in JET-ILW: the EUROfusion JET-ILW pedestal database

Pedestal structure, stability and scalings in JET-ILW: the EUROfusion JET-ILW pedestal database

Developments towards an ELM-free pedestal radiative cooling scenario using noble gas seeding in ASDEX Upgrade

Simulation of helium supersonic molecular beam injection in tokamak plasma*

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