题目：Study Galactic Cosmic Ray Solar Modulation in the heliosphere

　　报告人：罗熙（山东高等技术研究院研究员，2012年毕业于美国佛罗里达理工学院，理学博士。先后在中科院空间中心，南非西北大学，和美国夏威夷大学从事银河宇宙射线相关太阳物理研究。目前主要从事银河宇宙射线太阳调制和空间粒子辐射环境研究。在 PRL, APJ, JGR等期刊上累计发表论文15篇，主持国家自然科学基金委项目3项。）

　　摘要：As Galactic Cosmic Rays (GCRs) propagate into the heliosphere, they encounter the outward moving solar wind plasma. Because of the interaction with the solar wind plasma, the GCR intensity is reduced. Records of GCR intensity obtained by various experiments on Earth show that their intensity is related to the solar activity and solar disturbance. This phenomenon is called GCR solar modulation. Currently, it is widely accepted that the solar modulation of GCRs is due to a combination of various effects, which is expressed as the cosmic ray transport equation. With the aid of the heliospheric Magnet Hydrodynamic model, a fully 3D numerical model has already been established based on the GCR transport equation. Due to this hybrid numerical model, some understanding for the GCR distribution in the heliosphere has been achieved. Additionally, by numerical studying the GCR transport near the heliopause, the simulation results addressed the question for the solar modulation outer boundary and interpreted the Voyagers GCR observation near the heliopause. The Stochastic Differential Equation (SDE) method is time dependent, which we utilized to solve the GCR transport equation, provides a convenient way to simulate the GCRs transient events, e.g. Forbush decrease, Global Merged Interaction Regions. In this talk, I will also discuss some recent numerical work about the GCRs transient events, and some interesting new features revealed by these studies.

　　报告时间：2020年10月21日16:00

　　报告地点：腾讯会议室5032471346

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紫金山天文台学术委员会