Time: Monday, Jun. 1,10:00 am
Venue: ZJU Ding Talk
Speaker: Haowei Zhang
Title:Nonlinear interaction of toroidal Alfven eigenmodes and tearing modes
Abstract:
Hybrid kinetic-magnetohydrodynamic (MHD) simulation studies on nonlinear interaction of tearing modes (TMs) and toroidal Alfven eigenmodes (TAEs) are carried out with the CLT-K code. Force driven process of n=0 zonal flow generation by n=4 TAE is investigated. Most nonlinear characteristics, including the double growth rate and the radial mode structure of zonal flow, the decrease in TAE saturation level, etc., are basically consistent with previous researches (Todo, Berk et al. 2010 & 2012). Influences of n = 1 TM on n = 1 TAE (Zhu, Ma et al. 2018) are further studied. Nonlinear excitation of large amplitude zonal flow with the presence of n=1 TAE and n=1 TM is observed. The amplitude of TAE is then greatly reduced by zonal flow. Whereas the introduction of energetic particles (EPs) has a limited impact on the TM saturation, but results in a low rotation frequency of magnetic island in the ion-diamagnetic-drift direction. For the n=4 case, with the low 𝛃_𝐡 of EPs, the initially stable n = 4 TAE branch is destabilized by n = 1 TM with the same growth rate as the latter. The modulation on the EP current by the growing TM is found to be responsible for the TAE amplitude increasing.