Nonlinear self-interaction of geodesic acoustic modes in toroidal plasmas

M. Sasaki, K. Itoh, Y. Nagashima, A. Ejiri, Y. Takase

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


A self-nonlinear process involving the geodesic acoustic mode (GAM) was analyzed. GAMs nonlinearly excite higher harmonics as quasimodes. In the fluid picture, the Reynolds stress is modeled by the drift wave action. Other nonlinear terms such as the coupling between parallel velocity and vorticity, and between density and vorticity, were also considered, and evaluated using linear eigenmodes. We considered nonlinearities up to the third order. Analytic expressions for the amplitude of the second harmonic GAM and the saturation level of the fundamental GAM were derived. The validity of the theory is discussed based on a comparison of experimental results with theoretical predictions.

Original languageEnglish
Article number022306
JournalPhysics of Plasmas
Issue number2
Publication statusPublished - 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics


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