Time: 2012-10-19 14:00:00
Speaker: Zhiyong Qiu [IFTS]
Place: Rm. 413, Bld. 11#, Yuquan Campus
Abstract: Title:nonlinear excitation of geodesic acoustic mode by toroidal alfven eigenmode
Abstract:We apply the theory of Chen et al to spontaneous excitation of geodesic acoustic mode (GAM) by toroidal alfven eigenmode (TAE). It is shown that, spontaneous excitation of GAM by TAE is possible. Two cases are investigated. In the first case, m=0 zonal component of GAM is excited, and we found that, the parametric decay process is unstable only when the pump TAE frequency falls in the upper TAE gap. In the second case, m=1 poloidal harmonic of GAM is excited, which will then couple back to the zonal component via toroidicity. Resonant excitation and nonlinear scattering are both possible in this case due to possible strong Landau damping of GAM.