Development and testing of an unstructured mesh method for whole plasma gyrokinetic simulations in realistic tokamak geometry

Lu, Zhixin; Lauber, P.; Hayward-Schneider, T.; Bottino, A.; Hoelzl, M.

doi:10.1063/1.5124376

Cited by 13 publications

(16 citation statements)

References 36 publications

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“…The gyrokinetic codes are closest to first principles with the most important physics included, but re-quire long simulation times and consume significant amount of computing resources, especially when studying the nonlinear, multiple spatial and temporal scale physics [7,15,20]. A variety of codes made specific simplifications to achieve the balance between the computational cost and important physics.…”

Section: Simulation Models and Parametersmentioning

confidence: 99%

“…In the complex Gaussian expression A(s) = e −σ(s−s 0 ) 2 of radial envelope, the MSSB parameters σ and s 0 are obtained by fitting the radial mode structures simulated by the gyrokinetic eigenvalue code LIGKA [19], the initial value hybrid MHD-gyrokinetic code HMGC [17,18] and the full-f gyrokinetic code TRIMEG-GKX [15,16]. With the more consistent σ, s 0 as the input of HAGIS [6] code, the EP transport is studied.…”

Section: Physical Modelsmentioning

confidence: 99%

“…TRIMEG is a TRIangular MEsh based Gyrokinetic code with multiple species. It's originally developed using δ f method and the electrostatic kinetic model, using particle-in-cell in the poloidal plane and a particle-in-Fourier scheme in the toroidal direction [15]. It has been extended to handle electromagnetic kinetic problems including kinetic electrons using a full-f method, named TRIMEG-GKX [16].…”

Section: Gyrokinetic Full-f Code Trimeg-gkxmentioning

confidence: 99%

“…In this work, RSAEs driven by EPs and the related EP transport are studied by hybrid and gyrokinetic codes based on ASDEX-Upgrade parameters. The gyrokinetic full-f code TRIMEG-GKX [15,16], gyrokinetic/MHD hybrid code HMGC [17,18] and gyrokinetic eigenvalue code LIGKA [19] are employed to identify the quantitative connection between the MSSB and the EP profiles such as the maximum EP drive location. This paper is organized as follows.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mode structure symmetry breaking of reversed shear Alfvén eigenmodes and its impact on the generation of parallel velocity asymmetries in energetic particle distribution

Meng¹,

Lauber²,

Wang³

et al. 2021

Preprint

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In this work, the gyrokinetic eigenvalue code LIGKA, the drift-kinetic/MHD hybrid code HMGC and the gyrokinetic full-f code TRIMEG-GKX are employed to study the mode structure details of Reversed Shear Alfvén Eigenmodes (RSAEs). Using the parameters from an ASDEX-Upgrade plasma, a benchmark with the three different physical models for RSAE without and with Energetic Particles (EPs) is carried out. Reasonable agreement has been found for the mode frequency and the growth rate. Mode structure symmetry breaking (MSSB) is observed when EPs are included, due to the EPs' non-perturbative effects. It is found that the MSSB properties are featured by a finite radial wave phase velocity, and the linear mode structure can be well described by an analytical complex Gaussian expression A(s) = e −σ(s−s 0 ) 2 with complex parameters σ and s 0 , where s is the normalized radial coordinate. The mode structure is distorted in opposite manners when the EP drive shifted from one side of q min to the other side, and specifically, a non-zero average radial wave number k s with opposite signs is generated. The initial EP density profiles and the corresponding mode structures have been used as the input of HAGIS code to study the EP transport. The parallel velocity of EPs is generated in opposite directions, due to different values of the average radial wave number k s , corresponding to different initial EP density profiles with EP drive shifted away from the q min .

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Section: Simulation Models and Parametersmentioning

confidence: 99%

Section: Physical Modelsmentioning

confidence: 99%

Section: Gyrokinetic Full-f Code Trimeg-gkxmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mode structure symmetry breaking of reversed shear Alfvén eigenmodes and its impact on the generation of parallel velocity asymmetries in energetic particle distribution

Meng¹,

Lauber²,

Wang³

et al. 2021

Preprint

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show abstract

“…2. a mixed implicit-explicit scheme for particle simulations, with analytical simplifications, as a practical way to upgrade the TRIMEG code 14 , meanwhile also as a potential solution for JOREK and other existing codes 4,15,16 , for dealing with full f electromagnetic simulations;…”

Section: Introductionmentioning

confidence: 99%

The development of an implicit full f method for electromagnetic particle simulations of Alfvén waves and energetic particle physics

Meng²,

Hoelzl³

et al. 2020

Preprint

Self Cite

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In this work, an implicit scheme for particle-in-cell/Fourier electromagnetic simulations is developed and applied to studies of Alfvén waves in one dimension and in tokamak plasmas. An analytical treatment is introduced to achieve efficient convergence of the iterative solution of the implicit field-particle system. Its application to the one-dimensional uniform plasma demonstrates its applicability in a broad range of β/m e values. The toroidicity induced Alfvén eigenmode (TAE) is simulated using the widely studied case defined by the ITPA Energetic particle (EP) Topical Group. The real frequency and the growth (or damping) rate of the TAE with (or without) EPs agree with previous results reasonably well. The full f electromagnetic particle scheme established in this work provides a possible natural choice for EP transport studies where large profile variation needs to be captured in kinetic simulations.

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On Variational Fourier Particle Methods

Campos Pinto,

Ameres,

Kormann

et al. 2024

J Sci Comput

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In this article we describe a unifying framework for variational electromagnetic particle schemes of spectral type, and we propose a novel spectral Particle-In-Cell (PIC) scheme that preserves a discrete Hamiltonian structure. Our work is based on a new abstract variational derivation of particle schemes which builds on a de Rham complex where Low’s Lagrangian is discretized using a particle approximation of the distribution function. In this framework, which extends the recent Finite Element based Geometric Electromagnetic PIC (GEMPIC) method to a wide variety of field solvers, the discretization of the electromagnetic potentials and fields is represented by a de Rham sequence of compatible spaces, and the particle-field coupling procedure is described by approximation operators that commute with the differential operators involved in the sequence. For spectral Maxwell solvers these compatible spaces are spanned by a finite number of Fourier modes, and using $$L^2$$ L 2 projections as commuting operators leads to the gridless Particle-In-Fourier method which involves exact Fourier coefficients and continuous convolutions in the particle-field coupling. Our new variational PIC method, which we call Fourier-GEMPIC, is obtained by using a new sequence of commuting projections which combine discrete Fourier transforms (DFT), differentiation of particle shape functions and antiderivative filtering operators in Fourier space. As the resulting particle-field coupling essentially involves pointwise evaluations of shape functions and FFT (or DFT) algorithms on a sampling grid this method resembles usual spectral PIC methods, moreover a fully discrete scheme is derived using a directional Hamiltonian splitting procedure. The corresponding time steps are then given in closed form: they preserve the Gauss laws and the discrete Poisson bracket associated with the Hamiltonian structure. These explicit steps are found to share many similarities with a standard spectral PIC method that appears as a Gauss and momentum-preserving variant of the variational method. As arbitrary filters are allowed in our framework, we also discuss aliasing errors and study a natural back-filtering procedure to mitigate the damping caused by anti-aliasing smoothing particle shapes.

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Development and testing of an unstructured mesh method for whole plasma gyrokinetic simulations in realistic tokamak geometry

Cited by 13 publications

References 36 publications

Mode structure symmetry breaking of reversed shear Alfvén eigenmodes and its impact on the generation of parallel velocity asymmetries in energetic particle distribution

Mode structure symmetry breaking of reversed shear Alfvén eigenmodes and its impact on the generation of parallel velocity asymmetries in energetic particle distribution

The development of an implicit full f method for electromagnetic particle simulations of Alfvén waves and energetic particle physics

On Variational Fourier Particle Methods

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