Speaker
Description
Cosmic rays interacting with the solar atmosphere produce secondary high-energy gamma rays, but the observed solar gamma-ray emission still deviates from conventional theoretical expectations. Localized magnetic structures near the solar surface, especially coronal flux ropes associated with magnetic reconnection, may significantly affect the transport of incoming cosmic-ray protons and thus modulate solar gamma-ray production. In this work, we use the Geant4-based 3D simulation framework G4SOLAR to study proton transport and gamma-ray emission in a coronal flux-rope magnetic structure. The simulation includes a multilayer solar-atmosphere model and a local three-dimensional flux-rope field with characteristic scales of several $10^5$km and magnetic strengths of order a few gauss. By tracking proton trajectories, penetration depth, interaction sites, and secondary gamma rays, we find that the flux-rope structure can strongly modify proton transport near the solar surface and noticeably affect the spatial distribution and low-energy yield of solar gamma rays. Our results suggest that coronal flux ropes may be an important ingredient in understanding solar gamma-ray emission.
