Abstract The indirect nonlinear interactions between toroidal Alfvén eigenmode (TAE) and ion temperature gradient mode (ITG) are investigated using gyrokinetic theory ballooning formalism. More specifically, the local ITG equation is derived adopting fluid-ion approximation, with contributions of zonal field structure phase space beat-driven by finite amplitude TAE accounted for on same footing. obtained solved both analytically numerically, it found that, has only weakly destabilizing...

In this work, gyrokinetic theory of drift waves (DWs) self-regulation via the beat-driven zonal flow (ZF) is presented, and finite diamagnetic frequency due to plasma nonuniformity shown play a dominant role in ZF beat generation. The obtained nonlinear DW equation Schrödinger equation, which linear dispersiveness, growth, frequency, cubic nonlinearity induced by feedback DWs are self-consistently included. solved numerically both uniform nonuniform plasmas. It that envelope soliton may form...

Abstract The self-consistent nonlinear interaction of drift wave (DW) and zonal flow (ZF) is investigated
using gyrokinetic theory, with both spontaneous excitation beat-driven ZF by DW
treated on the same footing. DW solitons are formed in DW-ZF interactions are
confined between radially spaced micro-barriers induced spontaneously excited ZF. resulting
radial structures exhibit similar pattern to E×B“staircase”
observed numerical simulations. These...

General nonlinear equations describing reversed shear Alfvén eigenmode (RSAE) self-modulation via zero-frequency zonal structure (ZFZS) generation are derived using gyrokinetic theory, which then applied to study the spontaneous ZFZS excitation as well RSAE saturation. It is found that both electrostatic flow and electromagnetic current can be preferentially excited by finite-amplitude RSAE, depending on specific plasma parameters. The modification local wave continuum evaluated saturation...

The two-field equations governing fully nonlinear dynamics of the drift wave (DW) and geodesic acoustic mode (GAM) in toroidal geometry are derived gyrokinetic framework. Two stages with distinctive features identified analyzed. In linear growth stage, set can be reduced to intensively studied parametric decay instability (PDI), accounting for spontaneous resonant excitation GAM by DW. main results previous works on excitation, e.g., much enhanced group velocity rate GAM, reproduced from...

The local stability of ion-temperature gradient driven mode (ITG) in the presence a given radial electric field is investigated using gyrokinetic theory and ballooning formalism with toroidal effect accounted for. It found that, zero frequency induced poloidal rotation can significantly stabilize ITG, while associated density perturbation has little on ITG due to modification finite-orbit-width effect. However, parallel structure slightly affected evenly symmetric modulation ZFZF.

Nonlinear generation of high frequency modes (HFMs) by the toroidal Alfvén eigenmode (TAE) observed in HL-2A tokamak is analyzed using nonlinear gyrokinetic theory. It found that HFM can be dominated |nq−m|=1 perturbations with predominantly ideal magnetohydrodynamic polarization if two primary TAEs are copropagating, while characterized nq − m = 0 electrostatic counter-propagating. Here, n and poloidal mode numbers, respectively, q safety factor. The process sensitive to equilibrium...

Two novel nonlinear mode coupling processes for reversed shear Alfven eigenmode (RSAE) saturation are proposed and investigated. In the first process, RSAE nonlinearly couples to a co-propagating toroidal (TAE) with same poloidal numbers, generates geodesic acoustic (GAM). second counter-propagating TAE an ion wave quasi-mode (IAW). The condition two occur is favored during current ramp. Both contribute effectively saturate Alfvenic instabilities, as well transfer of energy from energetic...

The self-consistent nonlinear interaction of drift wave (DW) and zonal flow (ZF) is investigated using gyrokinetic theory, with both spontaneous excitation beat-driven ZF by DW treated on the same footing. solitons are formed in DW-ZF interactions confined between radially spaced micro-barriers. resulting radial structures exhibit similar pattern to ExB "staircase" observed numerical simulations. These micro-barriers generated repulsive response due spontaneously excited ZF, which, as a...

The indirect nonlinear interactions between toroidal Alfv\'en eigenmode (TAE) and ion temperature gradient mode (ITG) are investigated using gyrokinetic theory ballooning formalism. More specifically, the local ITG equation is derived adopting fluid-ion approximation, with contributions of zonal field structure phase space beat-driven by finite amplitude TAE accounted for on same footing. obtained solved both analytically numerically, it found that, has only weakly destabilizing effects ITG,...

In this work, gyrokinetic theory of drift waves (DWs) self-regulation via the forced driven zonal flow (ZF) is presented, and finite diamagnetic frequency due to plasma nonuniformity shown play dominant role in ZF generation. The obtained nonlinear DW equation a Schr\"odinger equation, which linear dispersiveness, growth, frequency, cubic nonlinearity induced by feedback forced-driven DWs are self-consistently included. solved numerically both uniform nonuniform plasmas. It that DWenvelope...

The evolution of the coupled drift wave (DW) and energetic-particle-induced geodesic acoustic mode (EGAM) nonlinear system is investigated using fully DW-EGAM two-field equations with emphasis on turbulence spreading in form soliton energy transfer between DW EGAM. Four scenarios different combinations EGAM initial amplitudes linear growth rates are designed to clarify contributions excitation by EPs DWs evolution. In presence drive, propagation enhanced, due generation small radial scale...

The evolution of the coupled drift wave (DW) and energetic-particle-induced geodesic acoustic mode (EGAM) nonlinear system is investigated using fully DW-EGAM two-field equations, with emphasis on turbulence spreading in form soliton energy transfer between DW EGAM. Four scenarios different combinations EGAM initial amplitudes linear growth rates are designed to delineate effects drive finite amplitude dynamic evolution. In presence EPs drive, propagation enhanced, due generation small...

The two-field equations governing fully nonlinear dynamics of the drift wave (DW) and geodesic acoustic mode (GAM) in toroidal geometry are derived gyrokinetic framework. Two stages with distinctive features identified analyzed. In linear growth stage, set can be reduced to intensively studied parametric decay instability (PDI), accounting for spontaneous resonant excitation GAM by DW. main results previous works on excitation, e.g., much enhanced group velocity rate GAM, reproduced from...