Particle-In-Cell (PIC) simulation is a powerful tool to study plasma kinetics. In this talk, I will show applying PIC method on the problems of astrophysical plasmas. Firstly, I present the modeling and interpretation of laser experiments designed to generate high Mach number magnetized collisionless shocks on OMEGA-EP facility. In the experiment, a laser-produced high velocity plasma collides with a magnetized, pre-ablated plasma. Proton radiography shows a moving region of proton deficit followed by a sharp enhancement of proton density. These features are produced by gradients in propagating compressed magnetic field. Our team compare the data to the results of 3D PIC simulations, explain the oblique moving features introduced by density gradients in expanding plasma and by curvature of the imposed magnetic field, and identify the narrowing of proton deficit region width with a signature of strong magnetic overshoot. We determine the boundary of pre-ablated background plasma by comparing with radiography of laser shots with only background plasma present. We measure the strength of magneto-inertial fusion electrical discharge system (MIFEDS) field by magnetic deflection. We conclude that our experiments have reproducibly achieved magnetized shocks with Alfvenic Mach number 3 to 9 in laboratory conditions. Secondly, we investigated 3-D linear instabilities of Harris current sheet under a realistic ion-to-electron mass ratio and a finite guide field. The excitation and 3-D properties of lower hybrid drift instability (LHDI) are demonstrated. We study the properties of current sheet instabilities by employing Gyrokinetic electron and Fully kinetic ion (GeFi) particle simulation code. It is found that part of the energy of the LHDI modes penetrates to the current sheet center in the nonlinear stage. The saturation level of magnetic field at the current sheet center is an order of magnitude smaller than that at the current sheet edge. The GeFi simulation results are compared with the fully kinetic PIC simulations.

大数据和大模型时代的天文学研究

大数据和大模型时代的天文学研究

本报告将展示人员、环境、心理等不同因素影响下行人动力学基本参数的变化规律，分析不同年龄构成特征人群运动基本图的统一条件，探索虚拟现实和人工智能技术在行人动力学和人员疏散研究中的应用。

本报告将展示航空器一旦发生火灾需要开展人员疏散时不同因素影响下人员疏散动力学过程，探索提升人员疏散效率和安全性的方法。

唐诗是中华优秀传统文化的突出代表，在当下的社会文化建设中发挥着培根铸魂的重要作用。特别是随着AI时代的到来，无论学术研究抑或经典传播，都需根据新的社会需要在不断反思中调整策略，加以推进；南宋严羽所著《沧浪诗话》，给我们提供了诸多有益的现代启示。