Nonlinear dynamics of toroidal Alfvén eigenmodes driven by energetic particles

Journal Article · Mon Jul 15 04:00:00 EDT 2013 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4816950· OSTI ID:22227953

Zhu, J.; Ma, Z. W. ^[1]; Fu, G. Y. ^[2]

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1. Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou, Zhejiang 310027 (China)
2. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

A kinetic simulation code based on a reduced model is developed to study dynamic evolutions of a single toroidicity-induced shear Alfvén eigenmode driven by energetic particles. For zero background damping, it is found that the wave amplitude in nonlinear phase can either saturate for weak energetic particle drives or slowly increase for strong drives. This slow nonlinear growth in strong drive cases is found to be associated with broadening and overlapping of resonances between the wave and trapped particles. For the near-marginal-stability case with a large background damping, the mode nonlinear evolution exhibits strong upward and downward frequency chirping in multiple branches. A hole/clump formation is observed clearly in the corresponding evolution of energetic particle distribution.

• OSTI ID: 22227953
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 20; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALFVEN WAVES
DAMPING
EIGENFUNCTIONS
EIGENVALUES
NONLINEAR PROBLEMS
PLASMA
PLASMA SIMULATION
PLASMA WAVES
SHEAR
TRAPPING