Authors: Weihao Liu (University of Michigan), Igor V. Sokolov (University of Michigan), Lulu Zhao (University of Michigan), Nishtha Sachdeva (University of Michigan), Ward B. Manchester IV (University of Michigan), Tamas I. Gombosi (University of Michigan)

Solar energetic particles (SEPs) can pose significant radiation hazards to spacecraft and crewed missions, while also offering valuable insights into particle acceleration and transport processes in the heliosphere. On 2017 September 10, a major SEP event associated with a fast coronal mass ejection (CME) was observed at Earth, the Solar TErrestrial RElations Observatory-Ahead (STA), and missions at Mars, including the Mars Atmosphere and Volatile EvolutioN mission, the Mars Express mission and the Curiosity rover on Mars surface.

In this study, we apply the SOlar Wind with FIeld lines and Energetic particles (SOFIE) model to simulate the event described above. Our results show that the ambient solar wind is comparable along the Earth, STA and Mars trajectory during the 27-day Carrington rotation centered on 2017 September 10. Comparisons between SOFIE-simulated CME evolution and white-light coronagraph observations, including the CME height-time profiles, show good agreement. We also employ the shock-capturing tool to identify the evolving shock surface and its properties for accelerating particles during the onset phase. Simulated SEP time-intensity profiles and spectral characteristics at Earth, STA, and Mars are evaluated against observations. This work supports the validation of the SOFIE model and advances its predictive capabilities, particularly in the context of ongoing Mars exploration efforts.