Title:  Study Galactic Cosmic Ray Solar Modulation in the heliosphere

Speaker: TAO Xi (Shandong University) 

Time: 10:00am, Oct. 21 (Wednesday)

Location: Tencent Conference Room 5032471346

Abstract: 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.