Weihao Liu, Lulu Zhao, Igor V. Sokolov, Kathryn Whitman, Tamas I. Gombosi, Nishtha Sachdeva, Eric T. Adamson, Hazel M. Bain, Claudio Corti, M. Leila Mays, Michelangelo Romano, Carina R. Alden, Madeleine M. Anastopulos, Mary E. Aronne, Janet E. Barzilla, Wesley T. Cook, Shawn D. Dahl, Hannah Hermann, Anthony J. Iampietro, A. Steve Johnson, Elizabeth A. Juelfs, Melissa R. Kane, Jonathan D. Lash, Kimberly Moreland, Briana K. Muhlestein, Teresa Nieves‐Chinchilla, Edward Semones, James F. Spann, Earl M. Spencer, Luke A. Stegeman, Christopher J. Stubenrauch, Kenneth L. Tegnell
Abstract The CLEAR Space Weather Center of Excellence's solar energetic particle (SEP) model, SOlar wind with FIeld lines and Energetic particles (SOFIE), was run and evaluated on‐site during the Space Weather Prediction Testbed (SWPT) exercise at the National Oceanic and Atmospheric Administration's Space Weather Prediction Center (NOAA/SWPC) in May 2025. As a physics‐based SEP model, SOFIE simulates the acceleration and transport of energetic particles by the coronal mass ejection (CME)‐driven shock in the solar corona and inner heliosphere, and has been validated against historical events. However, questions remain regarding whether a physics‐based model, traditionally considered computationally expensive, could meet operational needs. The SWPT exercise offered a valuable opportunity to evaluate SOFIE under simulated operational conditions. On‐site interactive feedback from SWPC forecasters, Space Radiation Analysis Group (SRAG) console operators, Community Coordinated Modeling Center (CCMC) personnel, and Moon‐to‐Mars Space Weather Analysis Office (M2M SWAO) analysts led to significant strategic improvements in the model configuration. The simulation grid was optimized by combining a coarser background grid with higher‐resolution regions along the CME path and toward Earth, reducing computational cost without compromising accuracy. In this work, we present the simulated operational performance of SOFIE and its capability to predict SEP fluxes significantly faster than real time. During the SWPT exercise, SOFIE completed a 4‐day SEP simulation within 5 hr using 1,000 central processing unit cores, although the earliest SEP forecast was obtained a few hours after CME onset. This marks a milestone in demonstrating SOFIE's operational usefulness and robustness to support future human space exploration.