Time: 2016-10-27 14:00:00 Speaker:Tao Wang, Chen Zhao[IFTS-ZJU] Place: Rm. 413, Bld. 11#, Yuquan Campus Abstract: Title: Characterization of Alfvén fluctuation spectra on realistic Tokamak scenarios Speaker: Tao Wang (王涛) Abstract: A reference scenario of Fusion Advanced Studies Torus (FAST) was studied by both “antenna” excitation and hybrid MHD-gyrokenetic simulations. FAST was designed to work in a dimensionless parameter range similar to ITER, and thus to study integrated ITER physics. Given the reference scenario, “antenna” excitation technique has been adopted with the aim of investigating the Alfvén fluctuation spectra, including Alfvén eigenmode frequency, damping rate and mode structures. In addition, this scenario was also studied by resonant excitation of energetic particles. Title: Gyrokinetic simulation and analytic modeling of DTEM physics Speaker: Chen Zhao (赵忱) Abstract: The trapped electron mode (TEM) instability is one of major candidates accounting for electron turbulent transport in a tokamak. In the tokamak pedestal, the collisional effects may become important due to the low temperature in this region. A particular type of TEM mode called dissipative trapped electron mode (DTEM) could be excited by the electron collisions. Recent EAST and HL-2A experiments show a plausible DTEM turbulence in the tokamak edge. Gyrokinetic simulations using GTC code are carried out to study the linear DTEM physics. An analytic model allows a unified treatment of various collisionality regimes, from the dissipative limit to the weakly collisional regime. Furthermore, both simulation and analytic theory reveal the key parametric dependences of the DTEM instability on wavelength. Comparisons between gyrokinetic simulation and analytic theory are carried out throughout this research.