基于Green函数法的太阳高能粒子行星际扩散过程模拟  

Simulation of the Diffusion Processes of Solar Energetic Particle Events Based on the Green Functional Theory

作　　者：朱琳玲 张效信[1,2] 顾斌 ZHU Linling;ZHANG Xiaoxin;GU Bin(Key Laboratory of Space Weather,National Satellite Meteorological Center(National Center for Space Weather),China Meteorological Administration,Beijing 100081;Innovation Center for FengYun Meteorological Satellite(FYSIC),Beijing 100081;Department of Physics,Nanjing University of Information Science and Technology,Nanjing 210044;Institute of Space Weather,Nanjing University of Information Science and Technology,Nanjing 210044)

机构地区：[1]中国气象局空间天气重点开放实验室/国家卫星气象中心(国家空间天气监测预警中心),北京100081 [2]许健民气象卫星创新中心,北京100081 [3]南京信息工程大学物理系,南京210044 [4]南京信息工程大学空间天气研究所,南京210044

出　　处：《空间科学学报》2022年第2期191-198,共8页Chinese Journal of Space Science

基　　金：国家自然科学基金项目(41931073,41774152);国家重点研发计划项目(2021YFA0718600)共同资助。

摘　　要：统计分析了自1976-2017年期间记录到的217次SEP(Solar Energetic Particle)事件的日冕足点经度位置,其分布特征符合日冕横向分布的东西效应,同时基于两相传输模型及其Green函数解,对发生在不同日冕足点的四次SEP事件进行了模拟研究。模拟与观测结果表现一致,表明该模型能够较好地模拟发生在不同日冕足点的SEP事件。针对模型中多个传输参数开展的敏感性试验发现,SEP事件日冕足点经度位置能够影响观测结果的探测时间和峰值,而太阳风速对发生在不同日冕足点的事件具有不同影响机制;此外,日冕区扩散系数与SEP事件在日冕区的扩散过程相关,主要影响事件的强度峰值;行星际径向扩散系数的改变对于模拟结果的影响主要体现在峰值到达时间上,且由于SEP事件主要是在大尺度的行星际磁场中传播,行星际径向扩散系数对于模拟结果的影响最为显著,而表征粒子源释放时间尺度的逃逸时间对于模拟结果影响相对较小。In order to investigate the diffusion processes of Solar Energetic Particle(SEP)events,four SEP events with different coronal-foot-point longitudes are simulated based on the two-phase model proposed by Huang et al.The simulations agree with the observations from GOES satellites,indicating that the model has wide applicability.Sensitivity tests for multiple transmission parameters in the model show that the change of the longitude of the coronal foot point affects the detection time and peak value of the observations,and the change of the solar wind speed has different influencing mechanisms to the SEP events with different coronal-foot-point longitudes.Furthermore,it can be found that the transverse diffusion coefficient of the corona area is associated with the diffusion processes of SEP events along the solar surface,and mainly affects the intensity of the event.Different radial diffusion coefficients mainly change the arrival time of the events,and it plays a more effective role in the diffusion of SEP events in comparison with the lateral diffusion coefficient,since the SEP events mainly transmit along the interplanetary magnetic field.In addition,the escape time that manifests the average lifetime of the SEP source or the time window for the outflow of SEPs from the solar activity,has the least effect on the simulations in comparison with the other parameters.

关 键 词：SEP事件 两相传输模型 GREEN函数 日冕区横向传输 行星际扩散 

分 类 号：P353[天文地球—空间物理学]