Time: 2011-12-21 15:00:00
Speaker: Zhiyong Qiu [IFTS]
Place: Rm. 413, Bld. 11#, Yuquan Campus
Abstract:
Title: Spatial-temporal evolution of the nonlinear DW-GAM system
Abstract: Kinetic effect and plasma nonuniformity plays an important role in the parametric excitation of GAM/KGAM by drift wave turbulence. In this work, we study the coupled equations between GAM/KGAM and DW sidebands, and investigate the effects of plasma nonuniformities such as GAM continuum, nonuniform DW frequency and nonuniform pump wave amplitude on GAM/KGAM excitation. We found that, the convective/absolute nature of the parametric instability is changed when nonuniform DW frequency is taken into account, and the growth rate scales as pump amplitude in the marginal unstable limit, while in the strong drive limit, a broad spectrum of modes are excited, and the growth rate of the most unstable mode scales as pump amplitude square.