Authors: Meng Jin (Lockheed Martin Solar and Astrophysics Lab)

Coronal Mass Ejection (CME) driven shocks are widely recognized as key drivers of gradual Solar Energetic Particle (SEP) events through the mechanism of diffusive shock acceleration. These SEP events present significant risks to both spaceborne technology and astronauts. Concurrently, particles accelerated at these shock fronts may also propagate back toward the Sun, potentially generating gamma-ray emissions via pion decay. This presentation delves into the critical role CME-driven shocks played in both the gamma-ray emissions and SEP events, integrating advanced modeling with the multi-messenger observations. Motivated by Fermi-LAT long-duration solar flares, we conducted a series of numerical simulations with the global Magnetohydrodynamic (MHD) AWSoM (Alfvén Wave Solar Model) to investigate the connection between CME-driven shocks and the properties of observed gamma-ray emissions. Additionally, by coupling the AWSoM model with physics-based particle acceleration and transport model iPATH, we evaluate the impact of shock evolution complexity near the Sun on SEP intensity and spectra. This complexity includes factors such as the inhomogeneous nature of the solar wind, the challenges in precise magnetic field-line tracking, and the occurrence of dual CME eruptions. Our result highlights the importance of accurate background coronal and solar wind modeling, as well as detailed observations of CME source regions, in enhancing our understanding of CME-driven shocks and the dynamics of associated energetic particles.