Time: 2016-05-05 14:00:00
Speaker: Dr. A. Biancalani, Tong Chen, Haotian Chen 陈通 陈昊天 [IFTS-ZJU]
Place: Rm. 413, Bld. 11#, Yuquan Campus
Abstract: Title: Gyrokinetic simulations of Alfven instabilities in tokamak plasmas
Speaker: Dr. A. Biancalani
Abstract: Alfven Eigenmodes (AE) are important in the dynamics of fusion plasmas, because they can redistribute the EP population, making the plasma heating less effective, and leading to additional loads on the walls. The linear and nonlinear dynamics of Alfven modes in the presence of EPs is investigated by means of the global gyrokinetic particle-in-cell code ORB5, within the NEMORB project [1,2,3]. The nonperturbative nonlinear interplay of these plasma instabilities and EPs is studied in different regimes of interest. In particular, we address the nonlinear modified spatiotemporal structures of Alfvénic fluctuations as a consequence of energetic particle transport.
References:
[1] S. Jolliet, et al., Comput. Phys. 177, 409 (2007)
[2] A. Bottino and E. Sonnendruecker, J. Plasma Phys. 81, 435810501 (2015)
[3] A. Biancalani, et al., Phys. of Plasmas 23, 012108 (2016)
Title: A more physical understanding of the off-diagonal pressure for the magnetic reconnection X-point
Speaker: Tong Chen
Abstract: Many magnetic reconnection X-point analysis would pay attention to the off-diagonal pressure term, which do not have very clear physical meaning in collisionless plasma. In this seminar, we try to analysis the detail on the X-point, and give a more physical understanding for this phenomenon.
Title: Drift Waves in the Strong Pressure Gradient Region
Speaker: Haotian Chen
Abstract: 2D theoretical analysis of drift eigenmodes in the strong pressure gradient region is presented through a gyrokinetic approach. Two types of modes are identified. It's demonstrated that poloidal harmonics may not localize at mode rational surfaces and the amplitude factors of different poloidal harminics vary greatly, the corresponding mode structures may not peak at the outboard side of the tokamak, and the correlation length is reduced.