The spatial and temporal evolution of parametrically excited geodesic acoustic mode (GAM) initial pulse is investigated both analytically and numerically. Our results show that the nonlinearly excited GAM propagates at a group velocity which is, typically, much larger than that due to finite ion Larmor radius as predicted by the linear theory. The nonlinear dispersion relation of GAM driven by a finite amplitude drift wave pump is also derived, showing a nonlinear frequency increment of GAM. Further implications of these findings for interpreting experimental observations are also discussed. © 2015 AIP Publishing LLC.
Titolo: | On fast radial propagation of parametrically excited geodesic acoustic mode |
Autori: | |
Data di pubblicazione: | 2015 |
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Handle: | http://hdl.handle.net/20.500.12079/1306 |
Appare nelle tipologie: | 1.1 Articolo in rivista |