The influence of magnetic field curvature on intermittency in drift-wave turbulence in the stellarator TJ-K

Garland, S.; Mänz, P.; Ramisch, M.

doi:10.1063/5.0004963

Cited by 4 publications

(2 citation statements)

References 45 publications

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“…Previous turbulence modelling of TJ-K was accomplished either through modified Hasegawa-Wakatani models in slab geometry [10,11] or by using a fluid model in a simplified geometry with the characteristic plasma parameters of TJ-K [12]. Due to their simplicity, a detailed one-to-one comparison of the simulations against experimental results was not attempted.…”

Section: Introductionmentioning

confidence: 99%

Validation of GBS plasma turbulence simulation of the TJ-K stellarator

Coelho

Loizu

Ricci

et al. 2023

Plasma Phys. Control. Fusion

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We present a validation of a three-dimensional, two-fluid simulation of plasma turbulence in the TJ-K stellarator, a low temperature plasma experiment ideally suited for turbulence measurements. The simulation is carried out by the GBS code, recently adapted to simulate 3D magnetic fields. The comparison shows that GBS retrieves the main turbulence properties observed in the device, namely the fact that transport is dominated by fluctuations with low poloidal mode number. The poloidal dependence of the radial $\text{E}\times\text{B}$ turbulent flux is compared on a poloidal plane with elliptical flux surfaces, where a very good agreement between experiment and simulation is observed, and on another with triangular flux surfaces, which shows a poorer comparison. The fluctuation levels in both cases are underestimated in the simulations. The equilibrium density profile is well retrieved by the simulation, while the electron temperature and the electrostatic potential profiles, which are very sensitive to the strength and localization of the sources, do not agree well with the experimental measurements.

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Section: Introductionmentioning

confidence: 99%

Validation of GBS plasma turbulence simulation of the TJ-K stellarator

Coelho

Loizu

Ricci

et al. 2023

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

show abstract

“…Garland et al [6] presented a study investigating the influence of collisionality on intermittency in drift-wave turbulence using both numerical and experimental approaches, the latter for the TJ-K stellerator; they showed an increase in intermittency with increasing collisionality for density fluctuations. The study in [7] revealed the importance of considering local curvature properties as a factor in the decoupling of density and potential fluctuations leading to intermittency in drift-wave turbulence.…”

Section: Introductionmentioning

confidence: 99%

Transport, flow topology and Lagrangian conditional statistics in edge plasma turbulence

Kadoch¹,

del‐Castillo‐Negrete²,

Bos³

et al. 2022

Preprint

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Lagrangian statistics and particle transport in edge plasma turbulence are investigated using the Hasegawa-Wakatani model and its modified version. The latter shows the emergence of pronounced zonal flows. Different values of the adiabaticity parameter are considered. The main goal is to characterize the role of coherent structures, i.e., vortices and zonal flows, and their impact on the Lagrangian statistics of particles. Computationally intensive long time simulations following ensembles of test particles over hundreds of eddy turnover times are considered in statistically stationary turbulent flows. The flow topology is characterized using the Lagrangian Okubo-Weiss criterion, and the flow can thus be split into topologically different domains. In elliptic and hyperbolic regions, the probability density functions (pdfs) of the residence time have self-similar algebraic decaying tails. However, in the intermediate regions the pdfs do exhibit exponentially decaying tails. Topologically conditioned pdfs of the Lagrangian velocity, and acceleration and density fluctuations are likewise computed. The differences between the classical Hasegawa-Wakatani system and its modified version are assessed and the role of zonal flows is highlighted. The density flux spectrum which characterizes the contributions of different length scales is studied and its inertial scaling is found to be in agreement with predictions based on dimensional arguments. Analyzing the angular change of particle tracers at different time scales, corresponding to coarse grained curvature, completes the study and the multiscale geometric statistics quantify the directional properties of the particle motion in the different flow regimes.

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Lagrangian conditional statistics and flow topology in edge plasma turbulence

et al. 2022

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Lagrangian statistics and particle transport in edge plasma turbulence are investigated using the Hasegawa–Wakatani model and its modified version. The latter shows the emergence of pronounced zonal flows. Different values of the adiabaticity parameter are considered. The main goal is to characterize the role of coherent structures, i.e., vortices and zonal flows, and their impact on the Lagrangian statistics of particles. Computationally intensive long time simulations following ensembles of test particles over hundreds of eddy turnover times are considered in statistically stationary turbulent flows. The flow topology is characterized using the Lagrangian Okubo–Weiss criterion in order to split the flow into topologically different domains. In elliptic and hyperbolic regions, the probability density functions (PDFs) of the residence time have self-similar algebraic decaying tails. However, in the intermediate regions, the PDFs exhibit exponentially decaying tails. Topologically conditioned PDFs of the Lagrangian velocity, and acceleration and density fluctuations are likewise computed. The differences between the classical Hasegawa–Wakatani system and its modified version are assessed, and the role of zonal flows is highlighted. The density flux spectrum, which characterizes the contributions of different length scales, is studied, and its inertial scaling is found to be in agreement with predictions based on dimensional arguments. Analyzing the angular change of particle tracers at different time scales, corresponding to coarse grained curvature, completes the study, and these multiscale geometric statistics quantify the directional properties of the particle motion in different flow regimes.

show abstract

The influence of magnetic field curvature on intermittency in drift-wave turbulence in the stellarator TJ-K

Cited by 4 publications

References 45 publications

Validation of GBS plasma turbulence simulation of the TJ-K stellarator

Validation of GBS plasma turbulence simulation of the TJ-K stellarator

Transport, flow topology and Lagrangian conditional statistics in edge plasma turbulence

Lagrangian conditional statistics and flow topology in edge plasma turbulence

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