Nonlinear excitation of finite-radial-scale zonal structures by toroidal Alfvén eigenmode

  title={Nonlinear excitation of finite-radial-scale zonal structures by toroidal Alfv{\'e}n eigenmode},
  author={Zhiyong Qiu and Liu Chen and Fulvio Zonca},
  journal={Nuclear Fusion},
The set of equations describing nonlinear evolution of a single toroidal Alfvén 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… 

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It is demonstrated theoretically that a toroidal Alfvén eigenmode (TAE) can parametrically decay into a geodesic acoustic mode and kinetic TAE in a toroid plasma, which could contribute to the heating as well as regulating the transports of thermal plasmas.

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Generation of zonal ow (ZF) by energetic particle (EP) driven toroidal Alfven eigenmode (TAE) is investigated using nonlinear gyrokinetic theory. It is found that, nonlinear resonant EP contri-

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Nonlinear saturation of toroidal Alfvén eigenmodes via ion compton scattering.

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It is shown that nonlinear ponderomotive force produced by TAE's interaction drives sound-wave-like density fluctuation with low phase velocity which can resonantly interact with the bulk ion parallel motion.

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