7月20日 五室第207期研讨会（邀请报告）

题  目: Particle simulation schemes with reduced electron models and the applications to plasma physics

报告人：Dr. Zhenyu Wang（PPPL）

主持人： 孙有文 研究员

时  间：  2023年7月20日（星期四 ）上午10:00-11:00

地  点：  8-2楼224会议室

摘  要：Particle simulation has been widely used in fusion plasma studies. In the past decades, reduced particle models, e.g. drift-kinetic, gyrokinetic model, are adopted in the simulations to accommodate the available computing resources. In this talk, I will describe the particle simulation models with fully kinetic ion and reduced electron models. First, we developed a novel differential geometry-based particle-in-cell (PIC) scheme with fully kinetic six-dimensional (6D) ions and adiabatic electrons on unstructured meshes, and apply it to study the quasi-kinetic equilibrium with spatial inhomogeneity and ion temperature gradient (ITG) instability and turbulence by full-f simulations. To search for a quasi-kinetic equilibrium with 1D spatial inhomogeneity and ITG turbulence, full-f PIC simulations with 6D ions and adiabatic electrons are carried out starting from a fluid equilibrium in the slab geometry. Relative to the quasi-kinetic equilibrium with 1D spatial inhomogeneity, the growth stage of the ITG mode is observed, it is also shown that at the nonlinear stage, zonal flow and potential blob formation are the most prominent features of the fully developed ITG turbulence.The rates of the ITG in the growth stage are compared with the gyrokinetic eigen value theory. Second, I will describe the gyrokinetic (GK) electron and fully kinetic (FK) ion particle (GeFi) simulation model and the particle simulation results of current sheet instabilities. In the GeFi model, the GK electron approximation removes the high frequency electron gyromotion and plasma oscillation, but the electron finite Lamor radii effects are retained. GeFi can properly address wave modes in the lower-hybrid and kinetic Alfven regimes when frequencies are higher or comparable to ion cyclotron frequencies, where ions must be treated as fully kinetic particles. For lower-hybrid waves, the GeFi results agree well with the fully kinetic explicit delta-f particle code. The 3-D GeFi and FK simulation results demonstrate the lower-hybrid-drift instability in current sheet under finite guide magnetic fields with the realistic proton-to-electron mass ratio.

欢迎感兴趣的人员参加！