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Related papers: Compressional Alfv\'en eigenmodes excited by runaw…

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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…

In the event of a tokamak disruption in a D-T plasma, fusion-born alpha particles take several milliseconds longer to thermalise than the background. As the damping rates drop drastically following the several orders of magnitudes drop of…

Plasma Physics · Physics 2023-04-19 Andrej Lier , Gergely Papp , Philipp Lauber , Istvan Pusztai , Konsta Särkimäki , Ola Embreus

Conditions for net fast ion drive are derived for beam-driven, co-propagating, sub-cyclotron compressional (CAE) and global (GAE) Alfv\'en eigenmodes driven by the Landau resonance with super-Alfv\'enic fast ions. Approximations applicable…

Plasma Physics · Physics 2023-02-10 J. B. Lestz , N. N. Gorelenkov , E. V. Belova , S. X. Tang , N. A. Crocker

Runaway particles can be produced in plasmas with large electric fields. Here we address the possibility that such runaway ions and electrons excite Alfv\'enic instabilities. The magnetic perturbation induced by these modes can enhance the…

Plasma Physics · Physics 2015-06-19 T Fülöp , S Newton

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…

The goal of magnetic fusion research is to extract the power released by fusion reactions and carried by the product of these reactions, liberated at energies of the order of a few MeV. The feasibility of fusion energy production relies on…

Plasma Physics · Physics 2009-12-15 Christine Nguyen

The aim of this study is to analyze the stability of Alfven Eigenmodes (AE) in the China Fusion Engineering Test Reactor (CFETR) plasma for steady state operations. The analysis is done using the gyro-fluid code FAR3d including the effect…

Plasma Physics · Physics 2023-04-18 J. Varela , J. Huang , D. A. Spong , J. Chen , V. Chan , L. Garcia , A. Wingen , Y. Ghai , Y. Zou

We report on a theoretical discovery of new regimes of Alfv\'en eigenmode (AE) induced fast ion transport in tokamak plasmas, where microturbulence plays the role of a mediator of fast ion relaxation. Coulomb collisional scattering alone…

Plasma Physics · Physics 2020-12-30 Nikolai Gorelenkov , Vinicius Duarte

Alfven Eigenmodes (AE) can be destabilized by energetic particles in neutral beam injection (NBI) heated plasmas through inverse Landau damping and couplings with gap modes in the shear Alfven continua. We describe the linear evolution of…

Plasma Physics · Physics 2017-10-11 J. Varela , D. Spong , L. Garcia

Fully self-consistent hybrid MHD/particle simulations reveal strong energetic particle modifications to sub-cyclotron global Alfv\'{e}n eigenmodes (GAE) in low-aspect ratio, NSTX-like conditions. Key parameters defining the fast ion…

Plasma Physics · Physics 2018-05-02 J. B. Lestz , E. V. Belova , N. N. Gorelenkov

Neutral-beam-driven, sub-cyclotron compressional (CAE) and global (GAE) \Alfven eigenmodes are routinely excited in spherical tokamaks such as NSTX(-U) and MAST, have been observed on the conventional aspect ratio tokamak DIII-D, and may be…

Plasma Physics · Physics 2021-08-11 J. B. Lestz

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

A comprehensive numerical study has been conducted in order to investigate the stability of beam-driven, sub-cyclotron frequency compressional (CAE) and global (GAE) Alfv\'en Eigenmodes in low aspect ratio plasmas for a wide range of beam…

Plasma Physics · Physics 2023-02-10 J. B. Lestz , E. V. Belova , N. N. Gorelenkov

Recent upgrades in H-1 power supplies have enabled the operation of the H-1 experiment at higher heating powers than previously attainable. A heating power scan in mixed hydrogen/helium plasmas reveals a change in mode activity with…

Plasma Physics · Physics 2017-11-22 M. J. Hole , B. D. Blackwell , G. Bowden , M. Cole , A. Konies , C. Michael , F. Zhao , S. R. Haskey

We present the first successful simulation of a induced disruption in ASDEX Upgrade from massive material injection (MMI) up to established runaway electron (RE) beam, thus covering pre-thermal quench, thermal quench and current quench (CQ)…

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

In geometrically symmetric capacitive radio-frequency plasmas driven by two consecutive harmonics a dc self-bias can be generated as a function of the phase shift between the driving frequencies via the Electrical Asymmetry Effect (EAE).…

Plasma Physics · Physics 2015-06-16 Ihor Korolov , Aranka Derzsi , Zoltan Donko , Julian Schulze

The formation of a substantial post-disruption runaway electron current in ASDEX Upgrade material injection experiments is determined by avalanche multiplication of a small seed population of runaway electrons. For the investigation of…

Conditions for net fast ion drive are derived for beam-driven, sub-cyclotron compressional (CAE) and global (GAE) Alfv\'en eigenmodes, such as those routinely observed in spherical tokamaks such as NSTX(-U) and MAST. Both co- and…

Plasma Physics · Physics 2023-02-10 J. B. Lestz , N. N. Gorelenkov , E. V. Belova , S. X. Tang , N. A. Crocker

ASDEX Upgrade has developed multiple massive gas injection (MGI) scenarios to investigate runaway electron (RE) dynamics. During the current quench of the MGI induced disruptions, Alfv\'enic activity is observed in the 300-800 kHz range.…

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