Nonlinear excitation of fine-radial-scale zonal structures by toroidal Alfven eigenmode

Abstract

The set of equations describing nonlinear evolution of a single toroidal Alfven eigenmode are derived, including both zero frequency zonal structure (ZFZS) generation and wave-particle phase space nonlinearities. The simplified case of neglecting wave-particle phase space nonlinearity is then investigated to focus on different roles of energetic particles and bulk plasmas on ZFZS generation. It is shown that energetic particles and bulk plasma play dominant roles in ZFZS generation in different nonlinear stages, and the corresponding processes are qualitatively different. Several properties of ZFZS generation, e.g., fine- vs. meso-scale, forced driven vs. spontaneous excitation, are clarified by the present analysis.

13 pages. Submited to Nuclear Fusion as the FEC2016 special issue paper

References in corpus (2)

• Nonlinear dynamics of phase space zonal structures and energetic particle physics in fusion plasmas
• Effects of energetic particles on zonal flow generation by toroidal Alfven eigenmode

Cited by in corpus (4)

• Nonlinear excitation of geodesic acoustic mode by toroidal Alfvén eigenmodes and impact on plasma performance
• Nonlinear reversed shear Alfven eigenmode saturation due to spontaneous zonal current generation
• Nonlinear coupling of reversed shear Alfven eigenmode and toroidal Alfven eigenmode during current ramp
• High frequency mode generation by toroidal Alfven eigenmodes