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|
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||1.1 Articolo in rivista|