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In scenarios where a sustained energetic particle source strongly drives toroidal Alfv\'en eigenmodes (TAE), and phase-space transport is insufficient to saturate TAE, this novel theory of TAE-zonal mode (ZM)-turbulence -- self-regulated by…

Plasma Physics · Physics 2025-03-03 Qinghao Yan , P. H. Diamond

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

The saturation of ion cyclotron Alfven turbulence excited by beam particles is investigated using resonance broadening theory. The stochastic scattering which decorrelates particles, includes both random acceleration by electric fields and…

Plasma Physics · Physics 2009-10-30 M. V. Medvedev , P. H. Diamond

A general theoretical framework for investigating nonlinear dynamics of phase space zonal structures is presented in this work. It is then, more specifically, applied to the limit where the nonlinear evolution time scale is smaller or…

Plasma Physics · Physics 2015-06-23 Fulvio Zonca , Liu Chen , Sergio Briguglio , Giuliana Fogaccia , Gregorio Vlad , Xin Wang

In this work, gyrokinetic theory of drift waves (DWs) self-regulation via the forced driven zonal flow (ZF) is presented, and finite diamagnetic drift frequency due to plasma nonuniformity is shown to play dominant role in ZF forced…

Plasma Physics · Physics 2024-02-13 Ningfei Chen , Liu Chen , Fulvio Zonca , Zhiyong Qiu

In tokamaks, turbulence is responsible not only for the anomalous transport of heat and particles from the core to the edge, which reduces heating efficiency, but also for the generation of zonal structures (ZSs). Examples of ZSs are those…

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

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

Nonlinear set of equations for inertial or slow shear Alfven wave (SSAW) in ideal electron-positron-ion (e-p-i) plasmas are presented. The analytical solution for arbitrary amplitude SSAW in such multi-component plasmas is obtained using…

Plasma Physics · Physics 2007-05-23 Shahzad Mahmood , H. Saleem

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

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

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

The self-consistent nonlinear interaction of drift wave (DW) and zonal flow (ZF) is investigated using nonlinear gyrokinetic theory, with both spontaneous excitation and beat-driven of ZF by DW treated on the same footing. DW solitons are…

Plasma Physics · Physics 2024-08-13 Ningfei Chen , Liu Chen , Fulvio Zonca , Zhiyong Qiu

A general equation describing the resonant nonlinear mode-coupling among kinetic Alfv\'en waves (KAWs) is derived using nonlinear gyrokinetic theory, which can be applied to study the potentially strong spectral energy transfer of KAWs. As…

Plasma Physics · Physics 2024-01-08 Kexun Shen , Zhiwen Cheng , Zhiyong Qiu

In homogeneous drift-wave (DW) turbulence, zonal flows (ZFs) can be generated via a modulational instability (MI) that either saturates monotonically or leads to oscillations of the ZF energy at the nonlinear stage. This dynamics is often…

Plasma Physics · Physics 2019-06-07 Hongxuan Zhu , Yao Zhou , I. Y. Dodin

Novel mechanisms for zonal flow (ZF) generation for both large relative density fluctuations and background density gradients are presented. In this non-Oberbeck-Boussinesq (NOB) regime ZFs are driven by the Favre stress, the large…

Plasma Physics · Physics 2018-07-13 Markus Held , Matthias Wiesenberger , Ralph Kube , Alexander Kendl

AC Josephson current density in a Josephson junction with DC bias is spatially modulated by an external magnetic field, and induces an electromagnetic (EM) field inside the junction. The current-voltage ($I$-$V$) curve exhibits peaks due to…

Superconductivity · Physics 2014-06-12 S. Hikino , M. Mori , S. Maekawa

Using one-dimensional numerical simulations, we study the elementary process of Alfv\'{e}n wave reflection in a uniform medium, including nonlinear effects. In the linear regime, Alfv\'{e}n wave reflection is triggered only by the…

Solar and Stellar Astrophysics · Physics 2016-04-13 Munehito Shoda , Takaaki Yokoyama

This paper presents a study of the interaction between Alfv\'en modes and zonal structures, considering a realistic ASDEX Upgrade equilibrium. The results of gyrokinetic simulations with the global, electromagnetic, particle-in-cell code…

Linear and nonlinear modelling of Alfv\'enic instabilities, most notably toroidal Alfv\'en eigenmodes (TAEs), obtained by using the global nonlinear electromagnetic gyrokinetic model of the code ORB5 are presented for the 15 MA scenario of…

Plasma Physics · Physics 2020-12-11 T. Hayward-Schneider , Ph. Lauber , A. Bottino , Z. X. Lu