A flux-balanced fluid model for collisional plasma edge turbulence: Numerical simulations with different aspect ratios

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Abstract

We investigate the drift wave-zonal flow dynamics in a shearless slab geometry with the new flux-balanced Hasegawa-Wakatani model. As in previous Hasegawa-Wakatani models, we observe a sharp transition from a turbulence dominated regime to a zonal jet dominated regime as we decrease the plasma resistivity. However, unlike previous models, zonal structures are always present in the flux-balanced model, even for high resistivity, and strongly reduce the level of particles and vorticity flux. The more robust zonal jets also have a higher variability than in previous models, which is further enhanced when the computational domain is chosen to be elongated in the radial direction. In these cases, we observe complex multiscale dynamics, with multiple jets interacting with one another, and intermittent bursts. We present a detailed statistical analysis which highlights how the changes in the aspect ratio of the computational domain affect the third-order statistical moments, and thus modify the turbulent dynamics. By changing the aspect ratio and extending either the radial or the binormal direction, the present model study offers a better approximation to mimic turbulence in flux tube simulations for either very low magnetic shear or very high magnetic shear systems.

Original languageEnglish (US)
Article number082303
JournalPhysics of Plasmas
Volume26
Issue number8
DOIs
StatePublished - Aug 1 2019

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collisional plasmas
aspect ratio
turbulence
fluids
simulation
shear
distribution moments
electrical resistivity
statistical analysis
vorticity
bursts
slabs
tubes
geometry
approximation

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

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title = "A flux-balanced fluid model for collisional plasma edge turbulence: Numerical simulations with different aspect ratios",
abstract = "We investigate the drift wave-zonal flow dynamics in a shearless slab geometry with the new flux-balanced Hasegawa-Wakatani model. As in previous Hasegawa-Wakatani models, we observe a sharp transition from a turbulence dominated regime to a zonal jet dominated regime as we decrease the plasma resistivity. However, unlike previous models, zonal structures are always present in the flux-balanced model, even for high resistivity, and strongly reduce the level of particles and vorticity flux. The more robust zonal jets also have a higher variability than in previous models, which is further enhanced when the computational domain is chosen to be elongated in the radial direction. In these cases, we observe complex multiscale dynamics, with multiple jets interacting with one another, and intermittent bursts. We present a detailed statistical analysis which highlights how the changes in the aspect ratio of the computational domain affect the third-order statistical moments, and thus modify the turbulent dynamics. By changing the aspect ratio and extending either the radial or the binormal direction, the present model study offers a better approximation to mimic turbulence in flux tube simulations for either very low magnetic shear or very high magnetic shear systems.",
author = "Di Qi and Andrew Majda and Antoine Cerfon",
year = "2019",
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T2 - Numerical simulations with different aspect ratios

AU - Qi, Di

AU - Majda, Andrew

AU - Cerfon, Antoine

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Y1 - 2019/8/1

N2 - We investigate the drift wave-zonal flow dynamics in a shearless slab geometry with the new flux-balanced Hasegawa-Wakatani model. As in previous Hasegawa-Wakatani models, we observe a sharp transition from a turbulence dominated regime to a zonal jet dominated regime as we decrease the plasma resistivity. However, unlike previous models, zonal structures are always present in the flux-balanced model, even for high resistivity, and strongly reduce the level of particles and vorticity flux. The more robust zonal jets also have a higher variability than in previous models, which is further enhanced when the computational domain is chosen to be elongated in the radial direction. In these cases, we observe complex multiscale dynamics, with multiple jets interacting with one another, and intermittent bursts. We present a detailed statistical analysis which highlights how the changes in the aspect ratio of the computational domain affect the third-order statistical moments, and thus modify the turbulent dynamics. By changing the aspect ratio and extending either the radial or the binormal direction, the present model study offers a better approximation to mimic turbulence in flux tube simulations for either very low magnetic shear or very high magnetic shear systems.

AB - We investigate the drift wave-zonal flow dynamics in a shearless slab geometry with the new flux-balanced Hasegawa-Wakatani model. As in previous Hasegawa-Wakatani models, we observe a sharp transition from a turbulence dominated regime to a zonal jet dominated regime as we decrease the plasma resistivity. However, unlike previous models, zonal structures are always present in the flux-balanced model, even for high resistivity, and strongly reduce the level of particles and vorticity flux. The more robust zonal jets also have a higher variability than in previous models, which is further enhanced when the computational domain is chosen to be elongated in the radial direction. In these cases, we observe complex multiscale dynamics, with multiple jets interacting with one another, and intermittent bursts. We present a detailed statistical analysis which highlights how the changes in the aspect ratio of the computational domain affect the third-order statistical moments, and thus modify the turbulent dynamics. By changing the aspect ratio and extending either the radial or the binormal direction, the present model study offers a better approximation to mimic turbulence in flux tube simulations for either very low magnetic shear or very high magnetic shear systems.

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