Nonlinear simulation and energy analysis of the EAST coherent mode

作者：Y.Q. Huang, Tianyang Xia, X. Q. Xu, Defeng Kong, Yumin Wang, Y. Ye, Z.H. Qian, Qing Zang, M.F. Wu, Yuqi Chu, Haiqing Liu, B. Gui, Xiangye Xiao, D.Z. Zhang · 发表于：Nuclear Fusion · 年份：2019 · DOI：10.1088/1741-4326/ab5e73 · 被引用次数：17 · 研究领域：Magnetic confinement fusion research、Ionosphere and magnetosphere dynamics、Particle accelerators and beam dynamics

The EAST coherent modes (CMs) during the inter-ELM phase are simulated by the electromagnetic six-field two-fluid module in BOUT++ framework. The fluctuation level of the electrostatic potential, electron pressure and density perturbations are comparable to the experiments, and the simulated electrostatic perturbation is around two orders of magnitude larger than the magnetic one in EAST CM. The frequency and poloidal wave number are consistent with experiments in the simulations of EAST CM equilibriums. The energy transfer between three-wave coupling indicates that the energy tends to transfer from medium-n to low-n modes in the early nonlinear phase, and the modes coupling effect in the nonlinear saturation phase is larger than that in the early nonlinear phase. Both the energy transfer and bispectral analysis show that the N i fluctuation tends to generate the 'single-mode' coupling and T e tends to be 'multiple-mode', which indicates that the collapse of the density profile is larger than the electron temperature. The relative phase analysis is applied to evaluate whether the turbulence can extract the energy from density and temperature profiles. The result indicates that the density profile provides much more energy to drive the turbulence than electron temperature. The kinetic and magnetic energy transfer rates are used to understand the instability and turbulence driving mechanisms of the EAST CM. In the linear phase of the nonlinear simulation, the instability is dri...