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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

The spatio-temporal evolution of the energetic particles in the transport time scale in tokamak plasmas is a key issue of the plasmas confinement, especially in burning plasmas. In order to include sources and sinks and collisional slowing…

Plasma Physics · Physics 2024-05-20 Guo Meng , Philipp Lauber , Zhixin Lu , Andreas Bergmann , Mirelle Schneider

The guiding centre dynamics of fast particles can alter the behaviour of energetic particle driven modes with chirping frequencies. In this paper, the applicability of an earlier trapped/passing locus model [H. Hezaveh et al 2017 Nucl.…

Plasma Physics · Physics 2021-05-12 Hooman Hezaveh , Zhisong Qu , Matthew Hole , Robert Dewar

In this work, an implicit scheme for particle-in-cell/Fourier electromagnetic simulations is developed and applied to studies of Alfv\'en waves in one dimension and three-dimensional tokamak plasmas. An analytical treatment is introduced to…

Plasma Physics · Physics 2021-02-03 Z. X. Lu , G. Meng , M. Hoelzl , Ph. Lauber

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

A general criterion is proposed and found to successfully predict the emergence of chirping oscillations of unstable Alfv\'enic eigenmodes in tokamak plasma experiments. The model includes realistic eigenfunction structure, detailed…

A dimensionless collisionality scan has been performed in H-mode plasmas on DIII-D tokamak, with detailed measurements of intermediate-to-high wavenumber turbulence using Doppler backscattering systems. It is found that the shorter…

Plasma Physics · Physics 2023-08-17 R. Hong , T. L. Rhodes , Y. Ren , P. H. Diamond , X. Jian , L. Zeng , K. Barada , Z. Yan , G. R. McKee

Following the analysis on linear spectra of shear Alfv\'en fluctuations excited by energetic particles (EPs) in the Divertor Tokamak Test (DTT) facility plasmas [T. Wang et al., Phys. Plasmas 25, 062509 (2018)], in this work, nonlinear…

Plasma Physics · Physics 2019-01-30 Tao Wang , Xin Wang , Sergio Briguglio , Zhiyong Qiu , Gregorio Vlad , Fulvio Zonca

The nonlinear dynamics of energetic particle (EP) driven geodesic acoustic modes (EGAM) in tokamaks is investigated, and compared with the beam-plasma system (BPS). The EGAM is studied with the global gyrokinetic (GK) particle-in-cell code…

Plasma Physics · Physics 2019-01-16 A. Biancalani , N. Carlevaro , A. Bottino , G. Montani , Z. Qiu

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

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…

In magnetically confined plasma, it is possible to qualitatively describe the magnetic field configuration via phase spaces of suitable symplectic maps. These phase spaces are of mixed type, where chaos coexists with regular motion, and the…

Plasma Physics · Physics 2023-11-09 Matheus S. Palmero , Iberê L. Caldas

Motivated by evidence for core-edge coupling in the form of double-peaked fishbone-like low-frequency modes ($\lesssim 20\,{\rm kHz}$) in KSTAR, which exhibit synchronized Alfv\'{e}nic activity both in the central core and near the plasma…

We investigate the ExB diffusion of fusion born \alpha particles in tokamak plasmas. We determine the transport regimes for a realistic model that has the characteristics of the ion temperature gradient (ITG) or of the trapped electron…

Plasma Physics · Physics 2017-02-01 A. Croitoru , D. I. Palade , M Vlad , F Spineanu

In [Viktorov M. E. et al., Eur. Phys. Lett., V.116, P.55001, 2016] we reported on chirping frequency patterns that have been observed in the electron cyclotron emission from strongly nonequilibrium plasma confined in a table-top mirror…

Plasma Physics · Physics 2019-06-10 A. G. Shalashov , E. D. Gospodchikov , M. E. Viktorov

Whistler mode chorus waves are quasi-coherent electromagnetic emissions with frequency chirping. Various models have been proposed to understand the chirping mechanism, which is a long-standing problem in space plasmas. Based on analysis of…

Plasma Physics · Physics 2021-10-04 Xin Tao , Fulvio Zonca , Liu Chen

A 1-D linear gyrokinetic code called AWECS is developed to study the kinetic excitation of Alfvenic instabilities in a high-beta tokamak plasma, with beta being the ratio of thermal to magnetic pressure. It is designed to describe physics…

Plasma Physics · Physics 2008-06-28 Andreas Bierwage , Liu Chen

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

In this work, we focus on the development of the particle-in-cell scheme and the application to the studies of Alfv\'en waves and energetic particle physics in tokamak plasmas. The $\delta f$ and full $f$ schemes are formulated on the same…

Plasma Physics · Physics 2022-10-11 Zhixin Lu , Guo Meng , Roman Hatzky , Matthias Hoelzl , Philipp Lauber

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