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Nonlinear saturation of toroidal Alfven eigenmode (TAE) via ion induced scatterings is investigated in the short-wavelength gyrokinetic regime. It is found that the nonlinear evolution depends on the thermal ion \b{eta} value. Here, \b{eta}…

Plasma Physics · Physics 2019-09-04 Zhiyong Qiu , Liu Chen , Fulvio Zonca

The parametric decay of toroidal Alfv\'en eigenmode (TAE) in nonuniform plasmas is investigated using nonlinear gyrokinetic equation. It is found that, the plasma nonuniformity not only significantly enhances the nonlinear coupling…

Plasma Physics · Physics 2024-03-06 Zhiwen Cheng , Kexun Shen , Zhiyong Qiu

Gyrokinetic theory of nonlinear mode coupling as a mechanism for toroidal Alfven eigenmode (TAE) saturation in the fusion plasma related parameter regime is presented, including 1) para- metric decay of TAE into lower kinetic TAE (LKTAE)…

Plasma Physics · Physics 2018-10-15 Zhiyong Qiu , Liu Chen , Fulvio Zonca , Wei Chen

The nonlinear saturation of toroidal Alfven eigenmode (TAE) due to thermal plasma nonlinearities is investigated using gyrokinetic particle-in-cell simulations and theoretical analysis. In the single toroidal mode number simulations with…

Geodesic acoustic modes (GAM) are oscillating zonal structures unique to toroidal plasmas, and have been extensively studied in the past decades due to their potential capabilities of regulating microscopic turbulences and associated…

Plasma Physics · Physics 2019-06-26 Zhiyong Qiu , Liu Chen , Fulvio Zonca

Nonlinear wave-wave coupling constitutes an important route for the turbulence spectrum evolution in both space and laboratory plasmas. For example, in a reactor relevant fusion plasma, a rich spectrum of symmetry breaking shear Alfv\'en…

Plasma Physics · Physics 2023-06-28 Zhiyong Qiu , Liu Chen , Fulvio Zonca

Two novel nonlinear mode coupling processes for reversed shear Alfven eigenmode (RSAE) nonlinear saturation are proposed and investigated. In the first process, RSAE nonlinearly couples to a co-propagating toroidal Alfven eigenmode (TAE)…

Plasma Physics · Physics 2021-03-18 Shizhao Wei , Yahui Wang , Peiwan Shi , Wei Chen , Ningfei Chen , Zhiyong Qiu

The excitation of toroidicity induced Alfv{\'e}n eigenmodes (TAEs) using prescribed external electromagnetic perturbations (hereafter ``antenna") acting on a confined toroidal plasma as well as its nonlinear couplings to other modes in the…

Toroidal Alfv\'en eigenmodes (TAEs) can transport fusion-born energetic particles out of the plasma volume, thereby decreasing plasma self-heating efficiency and possibly damaging reactor walls. Therefore, understanding TAE destabilisation…

Using electron drift wave (eDW) as a paradigm model, we have investigated analytically direct wave-wave interactions between a test DW and ambient toroidal Alfv\'en eigenmodes (TAE) in toroidal plasmas, and their effects on the stability of…

Plasma Physics · Physics 2023-06-28 Liu Chen , Zhiyong Qiu , Fulvio Zonca

The first linear global electromagnetic gyrokinetic particle simulation on the excitation of toroidicity induced Alfven eigenmode (TAE) by energetic particles is reported. With an increase in the energetic particle pressure, the TAE…

Plasma Physics · Physics 2009-11-13 Y. Nishimura

Turbulence in tokamaks generates radially sheared zonal flows. Their oscillatory counterparts, geodesic acoustic modes (GAMs), appear due to the action of the magnetic field curvature. The GAMs can be driven unstable by an anisotropic…

Generation of zonal ow (ZF) by energetic particle (EP) driven toroidal Alfven eigenmode (TAE) is investigated using nonlinear gyrokinetic theory. It is found that, nonlinear resonant EP contri- bution dominates over the usual Reynolds and…

Plasma Physics · Physics 2016-10-12 Zhiyong Qiu , Liu Chen , Fulvio Zonca

The confinement of energetic particles (EP) is crucial for an efficient heating of tokamak plasmas. Plasma instabilities such as Alfven Eigenmodes (AE) can redistribute the EP population making the plasma heating less effective, and leading…

Plasma Physics · Physics 2017-04-26 A. Biancalani , A. Bottino , M. Cole , C. Di Troia , Ph. Lauber , A. Mishchenko , B. Scott , F. Zonca

The indirect nonlinear interactions between toroidal Alfv\'en eigenmode (TAE) and ion temperature gradient mode (ITG) are investigated using nonlinear gyrokinetic theory and ballooning mode formalism. More specifically, the local nonlinear…

Plasma Physics · Physics 2024-08-29 Qian Fang , Guangyu Wei , Ningfei Chen , Liu Chen , Fulvio Zonca , Zhiyong Qiu

The nonlinear dynamics of beta-induced Alfv\'en Eigenmodes (BAE) driven by energetic particles (EP) in the presence of ion-temperature-gradient (ITG) turbulence is investigated, by means of selfconsistent global gyrokinetic simulations and…

Starting from the Braginskii equations, relevant for the tokamak edge region, a complete set of nonlinear equations for the geodesic acoustic modes (GAM) has been derived which includes collisionality, plasma beta and external sources of…

The energy input and frequency shift of geodesic acoustic modes (GAMs) due to turbulence in tokamak edge plasmas are investigated in numerical two-fluid turbulence studies. Surprisingly, the turbulent GAM dispersion relation is…

Plasma Physics · Physics 2015-05-30 Robert Hager , Klaus Hallatschek

Geodesic acoustic modes (GAMs) are studied by means of the gyrokinetic global particle-in-cell code ORB5. Linear electromagnetic simulations in the low electron beta limit have been performed, in order to separate acoustic and Alfv\'enic…

High-order plasma shaping (mainly elongation and shift, as opposed to low-order toroidicity) is shown, under certain conditions, to open gaps in the coupled shear-Alfv\'{e}n and acoustic continua at frequencies significantly above the…

Plasma Physics · Physics 2021-07-30 Paulo Rodrigues , Francesca Cella
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