Fine structure zonal flow excitation by beta-induced Alfvén eigenmode. (11th August 2016)

• Record Type: Journal Article
• Authors: Qiu, Zhiyong; Chen, Liu; Zonca, Fulvio
• Is Part Of: Nuclear fusion. Volume 56:Number 10(2016:Oct.)
• Publication Date: 2016-08-11
• Subjects: beta induced Alfvén eigenmode -- zonal structure -- zonal flow -- modulational instability -- nonlinear gyrokinetic theory; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/56/10/106013
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: Nonlinear excitation of low frequency zonal structure (LFZS) by beta-induced Alfvén eigenmode (BAE) is investigated using nonlinear gyrokinetic theory. It is found that electrostatic zonal flow (ZF), rather than zonal current, is preferentially excited by finite amplitude BAE. In addition to the well-known meso-scale radial envelope structure, ZF is also found to exhibit fine radial structure due to the localization of BAE with respect to mode rational surfaces. Specifically, the zonal electric field has an even mode structure at the rational surface where radial envelope peaks.