A5013589967- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
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- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Plasma Diagnostics and Applications
- Dust and Plasma Wave Phenomena
- Laser-induced spectroscopy and plasma
- Fusion materials and technologies
- Fluid Dynamics and Turbulent Flows
- Nuclear reactor physics and engineering
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- Metal and Thin Film Mechanics
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- Particle Dynamics in Fluid Flows
- Electromagnetic Launch and Propulsion Technology
- Gas Dynamics and Kinetic Theory
- GNSS positioning and interference
- Advanced Numerical Methods in Computational Mathematics
- Advancements in Semiconductor Devices and Circuit Design
- Pulsars and Gravitational Waves Research
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Max Planck Institute for Plasma Physics
2020-2024
Max Planck Computing and Data Facility
2020-2021
Lawrence Livermore National Laboratory
2016-2021
University of California, Irvine
2009-2020
Numerical Method (China)
2020
Max Planck Society
2020
Peking University
2016-2020
Oak Ridge National Laboratory
2010-2020
Institute of Physics
2020
Zhejiang University
2010-2020
JOREK is a massively parallel fully implicit non-linear extended MHD code for realistic tokamak X-point plasmas. It has become widely used versatile studying large-scale plasma instabilities and their control developed in an international community. This article gives comprehensive overview of the physics models implemented, numerical methods applied solving equations studies performed with code. A dedicated section highlights some verification work done hierarchy different available...
Recent results in the theory of turbulent momentum transport and origins intrinsic rotation are summarized. Special attention is focused on aspects critical to rotation, namely residual stress edge toroidal flow velocity pinch. Novel include a systematic decomposition physical processes which drive calculation external torque necessary hold plasma stationary against stress, simple model net scaling recovers salient features experimental trends elucidation impact particle flux Specific...
The fluid-kinetic hybrid electron model for global electromagnetic gyrokinetic particle simulations has been formulated in toroidal geometry using magnetic coordinates, providing the capabilities to describe low frequency processes turbulence with dynamics. In limit of long wavelength and no parallel electric field our equations reduce ideal magnetohydrodynamic equations. formulation generalized include equilibrium flows. zonal components electrostatic vector potentials have derived,...
Linear gyrokinetic simulation of fusion plasmas finds a radial localization the toroidal Alfv\'en eigenmodes (TAEs) due to nonperturbative energetic particle (EP) contribution. The EP-driven TAE has mode width much smaller than that predicted by magnetohydrodynamic theory. position stays around strongest EP pressure gradients when profile evolves. contribution is also main cause for breaking symmetry ballooning structure and dependence frequency on number. These phenomena are beyond picture...
A nonlinear oscillation of frequency and amplitude is found by massively parallel gyrokinetic simulations Alfv\'en eigenmodes excited energetic particles in toroidal plasmas. The fast repetitive chirping induced the evolution coherent structures phase space. dynamics controlled competition between phase-space island formation due to particle trapping destruction free streaming. provides a conceptual framework for understanding wave-particle interactions underlying transport process collisionless
The beta-induced Alfvén eigenmode (BAE) in toroidal plasmas is studied using global gyrokinetic particle simulations. BAE real frequency and damping rate measured the initial perturbation simulation antenna excitation agree well with each other. slightly higher than ideal magnetohydrodynamic (MHD) accumulation point due to kinetic effects of thermal ions. Simulations energetic density gradient show exponential growth a sensitive temperature density. nonperturbative contributions by particles...
Abstract Linear properties of the reverse shear Alfvén eigenmode (RSAE) in a well-diagnosed DIII-D tokamak experiment (discharge #142111) are studied gyrokinetic particle simulations. Simulations find that weakly damped RSAE exists due to toroidal coupling and other geometric effects. The mode is driven unstable by density gradients fast ions from neutral beam injection. Various damping driving mechanisms identified measured Accurate growth rate calculation requires non-perturbative, fully...
Developments in gyrokinetic particle simulation enable the toroidal code (GTC) to simulate turbulent transport tokamaks with realistic equilibrium profiles and plasma geometry, which is a critical step code–experiment validation process. These new developments include numerical representation using B-splines, Poisson solver based on finite difference field-aligned mesh magnetic flux coordinates, zonal flow for general improvements conventional four-point gyroaverage nonuniform background...
Abstract An important question for the outlook of stellarator reactors is their robustness against pressure driven modes, and underlying mechanism behind experimentally observed soft β limits. Towards building a robust answer to these questions, simulation studies are presented using recently derived reduced nonlinear MHD model. First, initial model implementation extended capture fluid compression by including influence parallel flows. Linear benchmarks (2, 1) tearing mode in W7-AS...
Comprehensive analysis of the largest first-principles simulations to date shows that stochastic wave-particle decorrelation is dominant mechanism responsible for electron heat transport driven by temperature gradient turbulence with extended radial streamers. The proportional local fluctuation intensity, and phase-space island overlap leads a diffusive process time scale comparable time, determined spectral width. This kinetic much shorter than fluid eddy mixing.
Global gyrokinetic particle simulations of reversed shear Alfvén eigenmode (RSAE) have been successfully performed and verified. We excited the RSAE by initial perturbation, external antenna, energetic ions. The excitation antenna provides verifications mode structure, frequency, damping rate. When kinetic effects background plasma are artificially suppressed, amplitude shows a near-linear growth. With thermal ions, eventually saturates due to ion damping. rates measured from perturbation...
A nonlinear gyrokinetic simulation model incorporating equilibrium current has been formulated for studying kinetic magnetohydrodynamic processes in magnetized plasmas. This complete formulation enables of both pressure-gradient-driven and current-driven instabilities as well their interactions multi-scale simulations. The recovers the ideal theory linear long wavelength regime including ballooning modes, kink modes shear Alfvén waves. implementation this global particle code verified...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation I. Holod, Z. Lin; Verification of electromagnetic fluid-kinetic hybrid electron model in global gyrokinetic particle simulation. Physics Plasmas 1 March 2013; 20 (3): 032309. https://doi.org/10.1063/1.4798392 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote...
Abstract An economic magnetic fusion reactor favours a high ratio of plasma kinetic pressure to in well-confined, hot with low thermal losses across the confining field. Field-reversed configuration (FRC) plasmas are potentially attractive as concept, achieving simple axisymmetric geometry. Here, we show that FRC have unique, beneficial microstability properties differ from typical regimes toroidal confinement devices. Ion-scale fluctuations found be absent or strongly suppressed core,...
A toroidal, nonlinear, electrostatic fluid-kinetic hybrid electron model is formulated for global gyrokinetic particle simulations of driftwave turbulence in fusion plasmas. Numerical properties are improved by an expansion the response using a smallness parameter ratio frequency to transit frequency. Linear accurately recover real and growth rate toroidal ion temperature gradient (ITG) instability. Trapped electrons increase ITG mostly not responding modes. Nonlinear find that thermal...
Gyrokinetic simulations of electrostatic driftwave instabilities in a tokamak edge have been carried out to study the turbulent transport pedestal an H-mode plasma. The use annulus geometry and focus on two radial regions DIII-D experiment: top with mild pressure gradient middle steep gradient. A reactive trapped electron instability typical ballooning mode structure is excited by electrons top. In pedestal, exhibits unusual structure, which peaks at poloidal angle θ=±π/2. find that this due...
The gyrokinetic toroidal code (GTC) capability has been extended for simulating internal kink instability with kinetic effects in geometry. global simulation domain covers the magnetic axis, which is necessary current-driven instabilities. GTC fluid limit of modes cylindrical geometry verified by benchmarking a magnetohydrodynamic eigenvalue code. Gyrokinetic simulations find that ion significantly reduce growth rate even when banana orbit width much smaller than radial perturbed current...
The collisionless trapped electron mode turbulence is investigated by global gyrokinetic particle simulation. zonal flow dominated low frequency and short wavelength acts as a very important saturation mechanism. turbulent eddies are mostly microscopic, but with significant portion in the mesoscale. ion heat transport found to be diffusive follows local radial profile of intensity. However, demonstrates some nondiffusive features only further confirmed nonlognormal statistics...
Linear properties of toroidal Alfvén eigenmode (TAE) is studied in global gyrokinetic particle simulations using both fast ion and antenna excitations. A synthetic provides a precise measurement the continuum gap width TAE frequency, damping rate, mode structures. The measured exhibits linear dependence on aspect ratio, agreement to local analytic theory. frequency structure excited by ions show significant radial symmetry breaking relative ideal magnetohydrodynamic theory due...
Abstract Vacuum resonant magnetic perturbations (RMP) applied to otherwise axisymmetric tokamak plasmas produce in general a combination of non-resonant effects that preserve closed flux surfaces (kink response) and introduce islands and/or stochasticity (tearing response). The effect the plasma kink response on linear stability nonlinear transport edge turbulence is studied using gyrokinetic toroidal code GTC for DIII-D with n = 2 vacuum RMP. simulations use 3D equilibrium discharge 158103...
Gyrokinetic simulations of DIII-D tokamak with axisymmetric equilibrium show that the reduction in radial electric field shear at top pedestal during edge localized mode (ELM) suppression n = 2 resonant magnetic perturbations (RMPs) leads to enhanced drift-wave turbulence and extended spreading relative ELMing plasmas similar RMP parameters. The simulated turbulent transport ELM suppressed conditions is consistent experimental observations by RMPs. These results imply due reduced can...
Global gyrokinetic particle simulations of electrostatic ion temperature gradient (ITG) instability show that the most unstable eigenmode is localized to some magnetic fieldlines or discrete locations on poloidal plane in Wendelstein 7-X (W7-X) stellarator due its mirror-like fields, which vary strongly toroidal direction and induce coupling more harmonics (n) form linear than Large Helical Device (LHD) stellarator. Nonlinear simulation results self-generated zonal flows are dominant...
The fast-electron driven beta-induced Alfvén eigenmode (e-BAE) in toroidal plasmas is investigated for the first time using global gyrokinetic particle simulations, where fast electron described by drift kinetic equation. simulation shows that e-BAE propagates diamagnetic direction and its polarization close to an ideal MHD mode. phase space structure only processional resonance responsible excitations while fast-ion BAE can be excited through all channels, including transit, bounce, resonance.
Transport scaling of energetic particles by ion temperature gradient microturbulence in magnetized plasmas is studied massively paralleled gyrokinetic particle-in-cell simulations. It found that the diffusivity decreases drastically at high energy (E) to plasma (T) ratio because averaging effects large gyroradius and drift-orbit width, fast wave-particle decorrelation. At energy, follows a (E/T)−1 for purely passing particles, (E/T)−2 deeply trapped with an isotropic velocity distribution...