Volume 107, Number 1, July 2014
|Number of page(s)||4|
|Section||Physics of Gases, Plasmas and Electric Discharges|
|Published online||09 July 2014|
On nonlinear geodesic acoustic modes in tokamak plasmas
1 Institute for Fusion Theory and Simulation and Department of Physics, Zhejiang University Hangzhou 310027, PRC
2 Department of Physics and Astronomy, University of California - Irvine, CA 92697-2575, USA
3 ENEA C. R. Frascati - C. P. 65-00044 Frascati, Italy
Received: 7 March 2014
Accepted: 17 June 2014
It is shown that, in tokamak plasmas, finite drift/banana-orbit width (FOW) effects play crucial roles in the nonlinear evolution of kinetic/geodesic acoustic modes (KGAM/GAM). In particular, it is found that, in contrast to the negligible second-harmonic generation, KGAM/GAM can generate appreciable zero-frequency zonal flow (ZFZF) due to the FOW effects. On the other hand, ZFZF is found to have negligible effects on the dynamics of GAM/KGAM. This route of generating ZFZF has important implications to the nonlinear dynamics of zonal flows and, consequently, drift wave turbulences.
PACS: 52.35.Mw – Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.) / 52.35.Fp – Electrostatic waves and oscillations (e.g., ion-acoustic waves) / 52.30.Gz – Gyrokinetics
© EPLA, 2014
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