太阳高能粒子峰值强度与积分通量的径向变化研究

Solar energetic particles (SEPs), produced by intense solar bursts, are harmful to the health of astronauts working in space and the electronic components on satellites, so they have become an important aspect in affecting solar-terrestrial space environment and space weather. Therefore, it is very important to achieve a better understanding of the transport processes and radiation effects of SEPs in the solar-terrestrial space. With combination of numerical simulation and data analysis, in this project we will systematically investigate the radial variations of peak intensities and fluences of SEPs, so as to study the physical mechanisms in the radial evolutions of SEP events, and establish useful functional relations for space radiation environment prediction. Firstly, based on previous works, we will further investigate the radial transport process of energetic protons in the outer heliosphere. Secondly, we will study the radial evolutions of energetic electrons and heavy ions in the global heliosphere. Thirdly, by means of large-scale numerical simulations of particles with different energies, we will obtain the radiation dosages and their radial variations in typical SEP events. In addition, we shall present quantitative physical explanations for the important observational phenomena in the field, and discuss the fundamental physical mechanisms therein. The results presented in this project will provide new insights for better understanding the radial transport processes of SEPs, and will lay solid theoretical bases for establishing physics-based forecast model of space radiation environment.

太阳高能粒子由太阳剧烈爆发活动产生，其对在太空中作业的宇航员和卫星上的电子元器件均构成严重危害，成为影响日地空间环境和空间天气的重要因素。因此，深入理解太阳高能粒子在日地空间中的传播过程及其辐射效应十分重要。本项目拟结合数值模拟和数据分析，对太阳高能粒子峰值强度与积分通量的径向变化开展系统、深入的研究，探索太阳高能粒子事件径向演化的物理机制，构建可用于空间辐射环境预报的函数关系。首先，将在前期研究基础上，进一步研究高能质子在外日球层的径向传播过程。其次，将探究高能电子和重离子在整个日球层的径向演化。再次，通过对不同能量粒子开展大规模数值模拟工作，将获得典型太阳高能粒子事件的辐射剂量及其径向变化。此外，将对领域中的重要观测现象给出定量的物理解释，探讨其中的基础性物理机制。本项目的研究成果将为深入理解太阳高能粒子的径向传播过程提供新视角，为构建基于物理的空间辐射环境预报模型奠定坚实的理论基础。

太阳高能粒子由太阳剧烈爆发活动（例如，耀斑、日冕物质抛射等）产生。太阳高能粒子对在太空中作业的宇航员和卫星上的电子元器件均构成严重危害，成为影响日地空间环境和空间天气的重要因素。因此，深入理解太阳高能粒子在日地空间中的传播过程及其辐射效应十分重要。本项目系统研究了太阳高能粒子在内日球层和外日球层的径向变化规律，确定了太阳高能粒子通量关系式R^-a（R为日心径向距离）中的重要指数a，探索了太阳高能粒子事件径向演化的重要物理机制——散射作用与绝热聚焦作用。本项目系统研究了太阳高能粒子“洪水”现象，并分析其形成机制，重新定义了高能粒子领域中盛行近30年的“水库”现象。此外，本项目分析了太阳高能粒子传播的背景条件——太阳风湍流特性的太阳周期变化规律。本项目的研究成果将为深入理解太阳高能粒子的径向传播过程提供新视角，为构建基于物理的空间辐射环境预报模型奠定理论基础。