On the afternoon of April 15, 2026, the 45th Deep Space Exploration Academic Salon was successfully held at the 1958 Café in the East Campus of the University of Science and Technology of China. Focusing on the topic of "energetic particles in the heliosphere", this salon conducted extensive discussions around particle acceleration theories, space weather effect and a series of simulation works, attracting many teachers, students and researchers to participate on site and engage in active discussions. The event invited Professor Gang Li from Macau University of Science and Technology and Researcher Fang Shen from the National Space Science Center to deliver two cutting-edge academic reports.

Professor Gang Li has long been engaged in the research on energetic particle acceleration and propagation mechanisms, space weather event processes and modeling. In his report entitled "Particle Acceleration and Propagation in the Inner Heliosphere and Space Weather", Professor Li compared the particle acceleration mechanism to the "gambling table rule", derived the mathematical form of the current mainstream energetic particle acceleration theory from this simple metaphor, and vividly clarified the physical image of the energetic particle acceleration process. Based on the understanding of the acceleration process in the source region, the professor introduced different sources of energetic particles in the heliosphere: solar energetic particle events accelerated by flares or CME-driven shocks, and galactic cosmic rays accelerated by supernova shocks outside the solar system. Among them, energetic particles from the Sun propagate and diffuse along the Parker spiral and reach the vicinity of the Earth. Galactic cosmic rays, on the other hand, propagate into the heliosphere under the control of the Parker transport equation, are modulated by solar activity, and can be quantified by theories such as the force-field model. The energetic particles arriving at the Earth are affected by the Earth's magnetosphere, regulated by the magnetic field that varies with geomagnetic latitude, and enter the upper atmosphere to varying degrees. The approximate capacitor composed of the conductive ground and the upper atmosphere will further respond to changes in the energetic particle flux. Finally, a space weather event chain of energetic particle acceleration, transmission, modulation and response was clearly established, which also covers the main research directions of Professor Li's team.

Researcher Fang Shen has long been deeply engaged in the field of space weather simulation and has achieved fruitful results. In her report entitled "Simulation Research on the Propagation of Solar Energetic Particles in Large-Scale Interplanetary Solar Wind Structures and Coronal Mass Ejections", she first introduced the simulation of the quiet solar wind: by solving the approximate MHD equations, the analytical solution of the physical field is given, and then observation data with high time resolution are input to realize the reconstruction of the background solar wind constrained by local observations. Through the physical description of coronal mass ejections and the integration of observation data, the team further realized the reconstruction of coronal mass ejection propagation, and innovatively used machine learning methods to efficiently capture the interplanetary shock structures driven by them. For shock-accelerated particles and particle transmission, the team also achieved the coupling by solving the Parker transport equation with other simulation modules. Based on the above systematic methods, the team successfully realized the complete reproduction of solar energetic particle events driven by coronal mass ejections and co-rotating interaction regions, and for individual typical events, conducted detailed comparative analysis between the simulation results and the observation data from multiple satellites. Relevant work has greatly made up for the observational limitations in energetic particle research, gave a new perspective for exploring the physical processes of particle acceleration and transmission, and also provided important technical support for accurate space weather forecasting.

The successful holding of this salon has built a high-level academic exchange bridge for researchers in the field of space science, especially energetic particles. The students participating on site spoke actively and asked questions, with sufficient academic interaction and remarkable exchange and sharing effects. In the future, the Deep Space Exploration Academic Salon will always be based on the international academic frontier, actively build an interdisciplinary exchange and cooperation platform, promote the collaborative innovation of deep space exploration with related fields such as Earth science and space physics, and provide strong support for the high-quality development of China's deep space exploration cause and the upgrading of interdisciplinary integration.

May we meet again amid the ongoing exploration of the cosmic frontier.

第45期深空探测学术沙龙：共探日球层高能粒子加速、传播的奥秘

2026年4月15日下午，第45期深空探测学术沙龙在中国科学技术大学东区1958咖啡厅顺利举办。本期沙龙聚焦“日球层高能粒子”话题，围绕粒子加速理论、空间天气响应及一系列模拟工作展开了广泛探讨，吸引了众多师生及科研工作者现场参与，积极讨论。活动邀请了澳门科技大学李刚教授与国家空间科学中心沈芳研究员带来两场前沿学术报告。

李刚教授长期从事高能粒子加速及传播机制、空间天气事件过程与建模研究，在他带来的题为“内日球层中的粒子加速与传播以及空间天气”的报告中，李刚教授将粒子的加速机制比作“赌桌法则”，从简单的比喻中推导出了目前主流的高能粒子加速理论的数学形式，形象阐明了高能粒子加速过程的物理图像。有了对源区加速过程的认识，教授引入了日球层高能粒子的不同源：即由耀斑或CME驱动激波加速的太阳高能粒子事件和来自太阳系外超新星激波加速的银河宇宙射线。其中来自太阳的高能粒子沿着帕克螺旋线传播扩散，到达地球附近。而银河宇宙射线则在帕克传输方程控制下向日球层内传播，受太阳活动的调制，并可由诸如力场模型的理论来量化。到达地球的高能粒子会受地球磁层影响，受到随地磁纬度变化的磁场调控，不同程度地进入高层大气。而由导电的地面和高层大气组成的近似电容器则会进一步对高能粒子通量的变化产生响应。最终，一个高能粒子加速、传输、调制、响应的空间天气事件链条被清晰地建立，也涵盖了李刚教授团队研究的主要方向。

  沈芳研究员长期深耕空间天气模拟领域，成果丰硕。在她题为“太阳高能粒子在行星际大尺度太阳风结构及日冕物质抛射中的传播模拟研究”的报告中，首先介绍了对平静太阳风的模拟：即通过求解近似MHD方程，给出物理场的解析解，再输入较高时间精度的观测数据，实现局地观测约束的背景太阳风重现。通过对日冕物质抛射的物理描述和观测数据整合，团队进一步实现了日冕物质抛射传播的重构，并创新性利用机器学习方法高效捕捉了其驱动的行星际激波结构。而针对激波加速粒子及粒子传输，团队也通过求解帕克传输方程与其余模拟模块实现耦合。基于上述系统方法，团队成功实现了对日冕物质抛射及共转相互作用区驱动的太阳高能粒子事件的完整复现，并针对个别典型事件，将模拟结果与多颗卫星的观测数据进行细致对比分析。相关工作很大程度弥补了高能粒子研究的观测局限性，为探究粒子加速及传输的物理过程提供了全新视角，也为空间天气精准预报提供了重要技术支撑。

  本次沙龙的成功举办为空间科学尤其是高能粒子领域的科研工作者搭建了高水平的学术交流桥梁，现场参加的同学踊跃发言提问，学术互动充分，交流共享效果显著。今后，深空探测学术沙龙将始终立足国际学术前沿，积极搭建跨学科交流合作平台，推动深空探测与地球科学、空间物理等相关领域的协同创新，为我国深空探测事业高质量发展与学科融合升级提供有力支撑。

愿每一次学术碰撞都能凝聚探索力量，每一次并肩同行都能迈向更远深空，我们期待与更多科研同仁、爱好者相聚相守，共赴逐梦宇宙、探秘星辰的璀璨征程。