Drift-wave stability in the field-reversed configuration

Lau, Calvin; Fulton, Daniel; Holod, I.; Zhang, Lin; Binderbauer, Michl; Tajima, T.; Schmitz, L.

doi:10.1063/1.4993630

Cited by 15 publications

(20 citation statements)

References 67 publications

(91 reference statements)

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“…Local linear simulations [11,12,13] using the gyrokinetic toroidal code (GTC) [14] have found qualitatively similar results. The SOL is linearly unstable for a wide range of length scales and varying pressure gradients.…”

Section: Introductionmentioning

confidence: 79%

Cross-separatrix simulations of turbulent transport in the field-reversed configuration

et al. 2019

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Recent local simulations of the field-reversed configuration (FRC) have reported drift-wave stability in the core and instability in the scrape-off layer (SOL). However, experimental measurements indicate the existence of fluctuations in both FRC core and SOL, with much lower amplitude fluctuations measured in the core. With the updated cross-separatrix capabilities of the simulation code used in this paper, nonlinear turbulence simulations find that linear instabilities grow in the SOL, generating fluctuations which spread from SOL to core. After saturation of the linear instabilities, a balance of the inward spread and local damping in the core is achieved. The steady state toroidal wavenumber spectrum shows lower amplitude core fluctuations and larger SOL fluctuations with amplitude decreasing towards shorter wavelengths, which are consistent with experimental measurements.

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Section: Introductionmentioning

confidence: 79%

Cross-separatrix simulations of turbulent transport in the field-reversed configuration

et al. 2019

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“…More detailed physics analysis will be reported in a forthcoming publication. 66 Prior to these simulations, simple test cases were run using both the new implementation and old less efficient (for FRC geometry) algorithms in GTC. We verified that the real frequency and growth rate from both sets of simulations matched, before undertaking more intensive simulations with the new implementation.…”

Section: Initial Simulation Resultsmentioning

confidence: 99%

“…68 More detailed theoretical analysis of the physics in both the FRC core and SOL will be discussed in a forthcoming publication. 66 Comparisons against experimental data will be reevaluated as the computational model is refined.…”

Section: Discussionmentioning

confidence: 99%

Gyrokinetic particle simulation of a field reversed configuration

et al. 2016

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Gyrokinetic particle simulation of the field-reversed configuration (FRC) has been developed using the gyrokinetic toroidal code (GTC). The magnetohydrodynamic equilibrium is mapped from cylindrical coordinates to Boozer coordinates for the FRC core and scrape-off layer (SOL), respectively. A field-aligned mesh is constructed for solving self-consistent electric fields using a semi-spectral solver in a partial torus FRC geometry. This new simulation capability has been successfully verified and driftwave instability in the FRC has been studied using the gyrokinetic simulation for the first time. Initial GTC simulations find that in the FRC core, the ion-scale driftwave is stabilized by the large ion gyroradius. In the SOL, the driftwave is unstable on both ion and electron scales. V C 2016 AIP Publishing LLC. [http://dx.

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“…Further analysis of particle phase space resonances is underway and will help complete the physical picture of the instabilities in the SOL. 29 Realistically, modelled input equilibrium suggests that the peak driving gradients occur in the SOL region, just outside the magnetic separatrix.…”

Section: Discussionmentioning

confidence: 99%

Gyrokinetic simulation of driftwave instability in field-reversed configuration

et al. 2016

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Following the recent remarkable progress in magnetohydrodynamic (MHD) stability control in the C-2U advanced beam driven field-reversed configuration (FRC), turbulent transport has become one of the foremost obstacles on the path towards an FRC-based fusion reactor. Significant effort has been made to expand kinetic simulation capabilities in FRC magnetic geometry. The recently upgraded Gyrokinetic Toroidal Code (GTC) now accommodates realistic magnetic geometry from the C-2U experiment at Tri Alpha Energy, Inc. and is optimized to efficiently handle the FRC's magnetic field line orientation. Initial electrostatic GTC simulations find that ion-scale instabilities are linearly stable in the FRC core for realistic pressure gradient drives. Estimated instability thresholds from linear GTC simulations are qualitatively consistent with critical gradients determined from experimental Doppler backscattering fluctuation data, which also find ion scale modes to be depressed in the FRC core. Beyond GTC, A New Code (ANC) has been developed to accurately resolve the magnetic field separatrix and address the interaction between the core and scrape-off layer regions, which ultimately determines global plasma confinement in the FRC. The current status of ANC and future development targets are discussed. Published by AIP Publishing.

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Drift-wave stability in the field-reversed configuration

Cited by 15 publications

References 67 publications

Cross-separatrix simulations of turbulent transport in the field-reversed configuration

Cross-separatrix simulations of turbulent transport in the field-reversed configuration

Gyrokinetic particle simulation of a field reversed configuration

Gyrokinetic simulation of driftwave instability in field-reversed configuration

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