A gyrokinetic continuum code based on the numerical Lie transform (NLT) method

Ye, Lei; Xu, Yingfeng; Xiao, Xiaotao; Dai, Zhujiang; Wang, Shaojie

doi:10.1016/j.jcp.2016.03.068

Cited by 37 publications

(39 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…two independent variables θ and ζ. The flux coordinates (ψ, θ, ζ) are previously employed in the NLT code [12], and it is straightforward to construct field-aligned coordinates ( ) x y z , , based on flux coordinates (ψ, θ, ζ) [8], e.g.…”

Section: Field-aligned Coordinates and Boundary Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

Implementation of field-aligned coordinates in a semi-Lagrangian gyrokinetic code for tokamak turbulence simulation

Xiao

et al. 2018

Plasma Sci. Technol.

Self Cite

View full text Add to dashboard Cite

Field-aligned coordinates have been implemented in the gyrokinetic semi-Lagrangian code NLT, Ye et al (2016 J. Comput. Phys. 316 180), to improve the computational efficiency for the numerical simulations of tokamak turbulence and transport. 4D B-spline interpolation in fieldaligned coordinates is applied to solve the gyrokinetic Vlasov equation. A fast iterative algorithm is proposed for efficiently solving the quasi-neutrality equation. A pseudo transform method is used for the numerical integration of the gyro-average operator for perturbations with a high toroidal mode number. The new method is shown to result in an improved code performance for reaching a given accuracy. Some numerical tests are presented to illustrate the new methods.

show abstract

Section: Field-aligned Coordinates and Boundary Conditionsmentioning

confidence: 99%

“…In this subsection, a brief introduction to the fundamental equations used in the NLT code are presented. For more detail on the I-transform theory and simulation model used in the NLT code, we refer the reader to [12,13,[19][20][21].…”

Section: Basic Equations In the Nlt Codementioning

confidence: 99%

Implementation of field-aligned coordinates in a semi-Lagrangian gyrokinetic code for tokamak turbulence simulation

Xiao

et al. 2018

Plasma Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…(38) and (39). It is worth to point out that the unperturbed orbit is independent of perturbations, which can be computed only once by using the high-precisional numerical algorithm in the initial of NLT simulation [20].…”

Section: Computation Of the Unperturbed Guiding Center Orbit Near Thementioning

confidence: 99%

“…In this paper, the numerical method to treat the magnetic axis in the electrostatic gyrokinetic nonlinear turbulence global code, NLT, by using field-aligned coordinates is presented. NLT is a continuum code based on the numerical Lie transform method [20,21]. The key idea of the numerical Lie transform method is to decouple the perturbed motion of the gyrocenter from the unperturbed motion, and the perturbed distribution function is obtained from the unperturbed one by using pull-back transform [22,23,24,25].…”

Section: Introductionmentioning

confidence: 99%

Gyrokinetic simulation of ITG turbulence with toroidal geometry including the magnetic axis by using field-aligned coordinates

Dai

et al. 2019

Computer Physics Communications

Self Cite

View full text Add to dashboard Cite

Simulation domain in field-aligned coordinates of the electrostatic gyrokinetic nonlinear turbulence global code, NLT, is extended to include the magnetic axis. The artificial boundary near the magnetic axis is replaced by the natural boundary. The singularity at the magnetic axis in Vlasov solver is treated by considering the spatial relation of fixed grid points in field-aligned coordinates. A new Poisson's equation solver is developed, the coefficient matrix of algebraic equations is derived by using Gauss's theorem. Nonlinear relaxation test of the ITG turbulence with adiabatic electrons is performed. The gyrocenter conservation is much improved by including the magnetic axis in the simulation domain. The zonal field and the radial distribution of the perturbed electrostatic potential are different from previous results without the magnetic axis.

show abstract

“…The nonlinear development of these instabilities, i.e., ITG turbulence, is believed to play an important role in regulating particle and heat transport in tokamaks [2][3][4]. There are numerous papers devoted to the gyrokinetic simulation of ITG turbulence, which employ gyrokinetic theory to decouple the high-frequency gyro-motion of ions from the low-frequency ITG modes [5][6][7][8][9][10]. However, gyrokinetics rely on ordering assumptions in deriving the gyrokinetic equation.…”

Section: Introductionmentioning

confidence: 99%

Fully Kinetic Simulation of Ion-Temperature-Gradient Instabilities in Tokamaks

Miecnikowski

Chen

et al. 2018

Plasma

View full text Add to dashboard Cite

The feasibility of using full ion kinetics, instead of gyrokinetics, in simulating low-frequency Ion-Temperature-Gradient (ITG) instabilities in tokamaks has recently been demonstrated. The present work extends the full ion kinetics to the nonlinear regime and investigates the nonlinear saturation of a single-n ITG instability due to the E × B trapping mechanism (n is the toroidal mode number). The saturation amplitude predicted by the E × B trapping theory is found to agree with the saturation level observed in the simulation. In extending to the nonlinear regime, we developed a toroidal Boris full orbit integrator, which proved to be accurate in capturing both the short-time scale cyclotron motion and long time scale drift motion, with good kinetic energy conservation and toroidal angular momentum conservation in tokamak equilibrium magnetic fields. This work also extends the previous work from analytic circular magnetic equilibria to general numerical magnetic equilibria, enabling simulation of realistic equilibria reconstructed from tokamak experiments.

show abstract

A gyrokinetic continuum code based on the numerical Lie transform (NLT) method

Cited by 37 publications

References 30 publications

Implementation of field-aligned coordinates in a semi-Lagrangian gyrokinetic code for tokamak turbulence simulation

Implementation of field-aligned coordinates in a semi-Lagrangian gyrokinetic code for tokamak turbulence simulation

Gyrokinetic simulation of ITG turbulence with toroidal geometry including the magnetic axis by using field-aligned coordinates

Fully Kinetic Simulation of Ion-Temperature-Gradient Instabilities in Tokamaks

Contact Info

Product

Resources

About