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Recent observations in HL-2A tokamak give new experimental evidences of energetic particle mode (EPM) avalanche. In a strong EPM burst, the mode structure propagates radially outward within two hundred Alfv\'en time, while the frequency of…

Hybrid MHD-gyrokinetic code simulations are used to investigate the dynamics of frequency sweeping reversed shear Alfv\'en eigenmode (RSAE) strongly driven by energetic particles (EPs) during plasma current ramp-up in a conventional tokamak…

Plasma Physics · Physics 2020-08-28 Tao Wang , Zhiyong Qiu , Fulvio Zonca , Sergio Briguglio , Gregorio Vlad

The aim of the study is to analyze the stability of the Energetic Particle Modes (EPM) and Alfven Eigenmodes (AE) in Helitron J and LHD plasma if the electron cyclotron current drive (ECCD) is applied. The analysis is performed using the…

Plasma Physics · Physics 2020-10-09 J. Varela , K. Nagasaki , K. Nagaoka , S. Yamamoto , K. Y. Watanabe , D. A. Spong , L. Garcia , A. Cappa , A. Azegami

Magnetohydrodynamic (MHD) turbulence is an important agent of energetic particle acceleration. Focusing on the compressible properties of magnetic turbulence, we adopt test particle method to study the particle acceleration from Alfv\'en,…

High Energy Astrophysical Phenomena · Physics 2021-12-08 Jianfu Zhang , Fuyuan Xiang

A novel 2D nonlinear dynamical paradigm is constructed to interpret the fast and repetitive frequency chirping and amplitude oscillation of Alfv\'en eigenmodes excited by energetic particles in fusion plasmas as observed in global…

Plasma Physics · Physics 2021-12-01 Junyi Cheng , Wenlu Zhang , Zhihong Lin , Jian Bao , Chao Dong , Jintao Cao , Ding Li

Nonlinear simulations of Alfv\'en modes (AM) driven by energetic particles (EP) in the presence of turbulence are performed with the gyrokinetic particle-in-cell code ORB5. The AMs carry a heat flux, and consequently they nonlinearly modify…

Toroidal Alfven eigenmodes (TAEs) excited in purely ohmically heated plasmas without any auxiliary heating have been identified for the first time in the SUNIST spherical tokamak. The TAE modes are observed during minor disruptions and have…

Plasma Physics · Physics 2016-12-26 Yangqing Liu , Yi Tan , Zhe Gao , Yuhong Xu , Youjun Hu , Song Chai , Yanzheng Jiang , Rui Ke , Heng Zhong , Wenhao Wang

The electron-cyclotron maser is a process that generates intense and coherent radio emission in plasma. In this paper, we present a comprehensive parametric investigation on the electron-cyclotron-maser instability driven by non-thermal…

Space Physics · Physics 2017-05-24 Zi-Jin Tong , Chuan-Bing Wang , Pei-Jin Zhang , Jin Liu

Alfv\'enic modes in the current quench (CQ) stage of the tokamak disruption have been observed in experiments. In DIII-D the excitation of these modes is associated with the presence of high-energy runaway electrons, and a strong mode…

Effects of circulating energetic particles on the geodesic acoustic modes (GAMs) with finite wave numbers are analyzed by using the hybrid kinetic-fluid model. The dispersion relation is derived by adopting the slowing beam ions…

Plasma Physics · Physics 2014-05-07 Haijun Ren

The aim of this study is to analyze the stability of the Alfven eigenmodes (AE) in the Chinese First Quasi-axisymmetric Stellarator (CFQS). The AE stability is calculated using the code FAR3d that solves the reduced MHD equations to…

Plasma Physics · Physics 2021-04-19 J. Varela , A. Shimizu , D. A. Spong , L. Garcia , Y. Ghai

The burning plasma performance is limited by the confinement of the superalfvenic fusion products such as alpha particles and the auxiliary heating ions capable of exciting the Alfv\'enic eigenmodes (AEs). In this work the effect of AEs on…

Plasma Physics · Physics 2018-08-01 Nikolai Gorelenkov , Vinicius Duarte , Mario Podesta , Herb Berk

The observation of rapidly variable very high energy (VHE) gamma-rays from non-aligned active galactic nuclei (AGNs), as reported from M87, proves challenging for conventional theoretical acceleration and emission models. We re-examine the…

Astrophysics · Physics 2009-11-13 F. M. Rieger , F. A. Aharonian

The linear properties of the low-frequency shear Alfv\'en waves such as those associated with the beta-induced Alfv\'en eigenmodes (BAEs) and the low-frequency modes observed in reversed-magnetic-shear DIII-D discharges (W. Heidbrink, et al…

Plasma Physics · Physics 2023-04-19 Ruirui Ma , W. W. Heidbrink , Liu Chen , Fulvio Zonca , Zhiyong Qiu

A self-consistent particle-in-cell simulation study is performed to investigate the effect of driving frequency on the electric field non-linearity, electron heating mechanism and electron energy distribution function (EEDF) in a low…

Plasma Physics · Physics 2020-04-22 Sarveshwar Sharma , Nishant Sirse , Animesh Kuley , Miles M Turner

Experimental investigations of the phase transition in GeTe provide contradictory conclusions regarding the nature of the phase transition. Considering growing interest in technological applications of GeTe, settling these disputes is of…

Materials Science · Physics 2022-10-13 Đorđe Dangić , Stephen Fahy , Ivana Savić

Finite-amplitude low-frequency Alfv\'en waves are commonly found in plasma environments, such as space plasmas, and play a crucial role in ion heating. The nonlinear interaction between oblique Alfv\'en wave spectra and ions has been…

Plasma Physics · Physics 2025-10-10 Jingyu Peng , Jiansen He

We have developed a hybrid code GMEC: Gyro-kinetic Magnetohydrodynamics (MHD) Energetic-particle Code that can numerically simulate energetic particle-driven Alfv\'en eigenmodes and energetic particle transport in tokamak plasmas. In order…

Plasma Physics · Physics 2024-02-23 Z. Y. Liu , P. Y. Jiang , S. Y. Liu , L. L. Zhang , G. Y. Fu

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 Alfv\'en Eigenmodes (RSAEs). Using the…

Plasma Physics · Physics 2021-07-16 Guo Meng , Philipp Lauber , Xin Wang , Zhixin Lu

Alfven Eigenmodes are destabilized at the DIII-D pedestal during transient beta drops in high poloidal beta discharges with internal transport barriers (ITBs), driven by n=1 external kink modes, leading to energetic particle losses. There…