Simulating gamma-ray production from cosmic rays interacting with the solar atmosphere in the presence of coronal magnetic fields  

作　　者：李哲 吳震宇 陈松战 南云程 何会海 Zhe Li;Kenny C.Y.Ng;Songzhan Chen;Yuncheng Nan;Huihai He(Institute of High Energy Physics,Chinese Academy of Science,Beijing 100049,China;Department of Physics,The Chinese University of Hong Kong,Shatin,New Territories,Hong Kong,China;School of Physical Sciences,University of Chinese Academy of Science,Beijing 100049,China)

机构地区：[1]Institute of High Energy Physics,Chinese Academy of Science,Beijing 100049,China [2]Department of Physics,The Chinese University of Hong Kong,Shatin,New Territories,Hong Kong,China [3]School of Physical Sciences,University of Chinese Academy of Science,Beijing 100049,China

出　　处：《Chinese Physics C》2024年第4期159-173,共15页中国物理C（英文版）

基　　金：the NSFC(12261160362,12022502);KCYN is supported by grants provided by the NSFC(12322517,N_CUHK456/22);RGC(24302721,14305822,14308023)。

摘　　要：Cosmic rays can interact with the solar atmosphere and produce a slew of secondary messengers,making the Sun a bright gamma-ray source in the sky.Detailed observations with Fermi-LAT have shown that these interactions must be strongly affected by solar magnetic fields in order to produce a wide range of observational features,such as a high flux and hard spectrum.However,the detailed mechanisms behind these features are still a mystery.In this study,we tackle this problem by performing particle-interaction simulations in the solar atmosphere in the presence of coronal magnetic fields using the potential field source surface(PFSS)model.We find that low-energy(~GeV)gamma-ray production is significantly enhanced by the coronal magnetic fields,but the enhancement decreases rapidly with energy.The enhancement directly correlates with the production of gamma rays with large deviation angles relative to the input cosmic-ray direction.We conclude that coronal magnetic fields are essential for correctly modeling solar disk gamma rays below 10 GeV,but above that,the effect of coronal magnetic fields diminishes.Other magnetic field structures are needed to explain the high-energy disk emission.

关 键 词：solar gamma-ray corona magnetic field Geant4 simulation hadronic interaction 

分 类 号：P182.62[天文地球—天文学] P172.3