Improved boundary condition for full‐f gyrokinetic simulations of circular‐limited tokamak plasmas in ELMFIRE

Chôné, L.; Kiviniemi, Timo; Leerink, S.; Niskala, P.; Rochford, R.

doi:10.1002/ctpp.201700185

Cited by 10 publications

(11 citation statements)

References 24 publications

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“…This large flux allowed a reduced computational cost of the simulation, as the L-H transition was due to fast electrostatic bifurcation occurring on a time scale considerably shorter than the one required to reach the global steady-state transport conditions. Other efforts to extend gyrokinetic codes to simulate turbulence in open-field-line systems include the Gkeyll (Shi et al 2017), GENE (Pan et al 2018), ELMFIRE (Chôné et al 2018) and COGENT (Dorf & Dorr 2020) codes. In this paper, we follow a different approach and we extend fluid simulations to the core region, in order to cover the whole tokamak plasma volume.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of turbulent transport regimes in the tokamak edge by using two-fluid simulations

Giacomin

Ricci

2020

J. Plasma Phys.

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The results of flux-driven, two-fluid simulations in single-null configurations are used to investigate the processes determining the turbulent transport in the tokamak edge. Three turbulent transport regimes are identified: (i) a developed transport regime with turbulence driven by an interchange instability, which shares a number of features with the standard L-mode of tokamak operation; (ii) a suppressed transport regime, characterized by a higher value of the energy confinement time, low-amplitude relative fluctuations driven by a Kelvin–Helmholtz instability, a strong $\boldsymbol {E}\times \boldsymbol {B}$ sheared flow and the formation of a transport barrier, which recalls the H-mode; and (iii) a degraded confinement regime, characterized by a catastrophically large interchange-driven turbulent transport, which recalls the crossing of the Greenwald density limit. We derive an analytical expression of the pressure gradient length in the three regimes. The transition from the developed transport regime to the suppressed transport regime is obtained by increasing the heat source or decreasing the collisionality and vice versa for the transition from the developed transport regime to the degraded confinement regime. An analytical expression of the power threshold to access the suppressed transport regime, linked to the power threshold for H-mode access, as well as the maximum density achievable before entering the degraded confinement regime, related to the Greenwald density, are also derived. The experimental dependencies of the power threshold for H-mode access on density, tokamak major radius and isotope mass are retrieved. The analytical estimate of the density limit contains the correct dependence on the plasma current and on the tokamak minor radius.

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Section: Introductionmentioning

confidence: 99%

“…2018), ELMFIRE (Chôné et al. 2018) and COGENT (Dorf & Dorr 2020) codes. In this paper, we follow a different approach and we extend fluid simulations to the core region, in order to cover the whole tokamak plasma volume.…”

Section: Introductionmentioning

confidence: 99%

Investigation of turbulent transport regimes in the tokamak edge by using two-fluid simulations

Giacomin

Ricci

2020

J. Plasma Phys.

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“…We refer to these boundary conditions as conducting-sheath boundary conditions 14,15 because they allow self-consistent currents locally in and out of the end plates. This is in contrast to the logical-sheath boundary-condition model, [65][66][67] which assumes an insulating sheath with zero current density at the end plates everywhere. There is no closed-field-line region in our present model.…”

Section: Modelmentioning

confidence: 96%

Full-f gyrokinetic simulation of turbulence in a helical open-field-line plasma

et al. 2019

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Curvature-driven turbulence in a helical open-field-line plasma is investigated using electrostatic fivedimensional gyrokinetic continuum simulations in an all-bad-curvature helical-slab geometry. Parameters for a National Spherical Torus Experiment scrape-off-layer plasma are used in the model. The formation and convective radial transport of plasma blobs is observed, and it is shown that the radial particle-transport levels are several times higher than diffusive Bohm-transport estimates. By reducing the strength of the poloidal magnetic field, the profile of the heat flux to the divertor plate is observed to broaden.

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“…Particle-in-cell (PIC) methods have accomplished a solution of this equation in both open and closed field lines; the XGC1 code, for example, has made valuable contributions to the prediction of heat-flux loads in current and future devices 19 . There is interest in cross-validating XGC1 results and also improving on its description of laboratory plasmas, for which other gyrokinetic codes are being developed, including GENE 20 , GYSELA 21 , ELMFIRE 22 , PICLS 23 and COGENT 24 . Among continuum codes, Gkeyll pioneered the simulation of gyrokinetic turbulence in open field lines 25 .…”

Section: Motivation and Overviewmentioning

confidence: 99%

Fluid & Gyrokinetic turbulence in open field-line, helical plasmas

Francisquez,

Bernard,

Zhu

et al. 2020

Preprint

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Improved boundary condition for full‐f gyrokinetic simulations of circular‐limited tokamak plasmas in ELMFIRE

Cited by 10 publications

References 24 publications

Investigation of turbulent transport regimes in the tokamak edge by using two-fluid simulations

Investigation of turbulent transport regimes in the tokamak edge by using two-fluid simulations

Full-f gyrokinetic simulation of turbulence in a helical open-field-line plasma

Fluid & Gyrokinetic turbulence in open field-line, helical plasmas

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