Influence of injection parameters on fueling efficiency of supersonic molecular beam injection into turbulent fusion plasmas

Avdeeva, G.; Naulin, V.; Nielsen, A. H.; Rasmussen, Jens Juul; Thrysøe, A. S.

doi:10.1063/5.0002858

Cited by 2 publications

(4 citation statements)

References 38 publications

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“…What remains now is to calculate the moments of the kinetic source term, i.e., Sσ = S n σ + S u σ + S T σ , due to changes in the fluid variables, defined in (6)(7)(8). The fluid density source for a Maxwell distribution function is…”

Section: Moments Of Kinetic Source Termsmentioning

confidence: 99%

“…When a fluid, such as a plasma, is created, e.g., by ionization of neutral atoms, this is, however, not guaranteed. The sources must therefore be derived from (6)(7)(8) where, for ionization, the kinetic source term, Sσ, depends on the neutral velocity distribution function fn. A detailed derivation of the electron impact ionization fluid source terms can be found in, e.g., [28] and result in the source terms for density…”

Section: Fluid Variable Source Terms From Ionizationmentioning

confidence: 99%

“…The profiles at the plasma edge and Scrape-Off Layer (SOL) regions determine the exhaust of particles and heat from the core and are central in regulating the machine performance [1]. The sources at the colder plasma boundary originate largely from the interactions with the neutral atoms and molecules, and the impact of the interactions on the plasma transport is subject to current attention in both experiments [2,3] and simulations [4][5][6][7][8][9][10][11][12]. In particular, such effects as fuelling, divertor detachment [1,[13][14][15] and SOL density shoulder formation [2,[16][17][18][19][20], depend on the plasma-neutral interactions.…”

Section: Introductionmentioning

confidence: 99%

“…A successful approach to modeling the plasma edge and SOL dynamics is to describe the plasma in the two-fluid picture [21], where ions and electrons each constitute a fluid with its own density, momentum, and temperature, although the charge densities of electrons and ions are commonly assumed equal due to quasi-neutrality. The family of edge and SOL codes [4][5][6][7][9][10][11][12], based on the two-fluid model, are extended within the past years to additionally model transport of neutral particles and the corresponding sources to the fluid plasma species.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the interpretation of kinetic effects from ionization in fluid models and its impact on filamentary transport

2023

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In regions where a plasma is not fully ionized, such as the edge and scrape-off layer (SOL) regions in a tokamak, the charged particles may be subject to strong sources from interactions with neutral atoms and molecules. Such sources, e.g., from electron impact ionization, can introduce kinetic effects, as the ionized particles may have flow velocity and temperature different from that of the main species. If treated in the conventional fluid picture, this kinetic effect emerges as a frictional heating term. In this paper, the physics of this term is discussed, both for un-magnetized and magnetized plasmas. The fluid source terms are mapped back to the kinetic sources to provide a consistent picture for future model comparison. In the limits of low and high ratios between the rates of thermalization and ionization, a multi-ion species drift-fluid model is applied to assess the impact of this kinetic effect on SOL drift-plane plasma transport. This is done by modeling a seeded blob where the ions follow either a single- or double-Maxwellian velocity distribution function (VDF). It is found that the robustness of the magnetized plasma VDF in the drift-plane and the limited effect on the vorticity source ensure that the impact of kinetic effects on the perpendicular blob evolution is small, even in the limit of high ionization to thermalization rate ratio, where kinetic effects to the ion VDF are significant.

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Section: Moments Of Kinetic Source Termsmentioning

confidence: 99%

Section: Fluid Variable Source Terms From Ionizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the interpretation of kinetic effects from ionization in fluid models and its impact on filamentary transport

2023

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A direct Monte Carlo approach for the modeling of neutrals at the plasma edge and its self-consistent coupling with the 2D fluid plasma edge turbulence model HESEL

Kvist,

Thrysøe,

Haugbølle

et al. 2024

Physics of Plasmas

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This paper presents a novel coupling of a kinetic description of neutrals with a fluid description of a fusion plasma. The code, plasma interacting super-atoms and molecules (PISAM), employs a grid-free Cartesian geometry and a direct simulation Monte Carlo approach to solve the kinetic equations of deuterium atoms and molecules. The grid-free geometry and the parallel nature of the neutral dynamics, in the absence of neutral–neutral interactions, allow for an unlimited and work-efficient parallelization of PISAM that always ensures a balanced workload. The highly optimized Python implementation obtains good performance while securing easy accessibility to new users. The coupling of PISAM with the edge turbulence model HESEL is outlined with emphasis on the technical aspects of coupling Message Passing Interface-parallelized Python and C++ codes. Furthermore, the paper presents and analyzes simulation results from running the coupled HESEL-PISAM model. These results demonstrate the impact of radial neutral transport and plasma–neutral dynamics perpendicular to the magnetic field. Specifically, they illustrate how the inward flow of neutral kinetic energy and the inhibition of radial electric shear, resulting from poloidal momentum transfer between atoms and ions, can affect the energy containment time. By comparing the results of the HESEL-PISAM model with those obtained from coupling HESEL with a diffusive-fluid-neutral model, the capabilities of diffusion models in predicting neutral transport in the plasma edge and scrape-off layer are elucidated.

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Influence of injection parameters on fueling efficiency of supersonic molecular beam injection into turbulent fusion plasmas

Cited by 2 publications

References 38 publications

On the interpretation of kinetic effects from ionization in fluid models and its impact on filamentary transport

On the interpretation of kinetic effects from ionization in fluid models and its impact on filamentary transport

A direct Monte Carlo approach for the modeling of neutrals at the plasma edge and its self-consistent coupling with the 2D fluid plasma edge turbulence model HESEL

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