Authors: Xiaohang Chen (University of Arizona), Athanasios Kouloumvakos (APL, Johns Hopkins University), Joe Giacalone (University of Arizona), Alexis Rouillard (CNRS)

We simulate the spatial and temporal evolution of SEPs acceleration at an interplanetary shock by combining the coronagraphic observations, global MHD model (ENLIL) and Parker transport equation. We reconstruct the 3D shock structures with coronagraphic observations and derive the distribution of shock parameters along the entire front based on the upstream plasma and magnetic field properties from ENLIL model. The coronagraphic observations provide the shock geometry evolution below ~30 solar radii. Beyond this range, we extrapolate the reconstruction to 1AU by fitting the shock velocity and radius. Then, we simulate the SEP acceleration and transport by numerically solving the Parker transport equation in 3D.  To test this model, we consider the Ground Level Enhancement Event No.72 on 2017/09/10 and compare the simulation results with the measurements from ACE and STEREO-A. This new model will help us better understand the evolution of SEP acceleration and provide new insights into large SEP events observed by multi-spacecraft, especially those close to the Sun, e.g., Parker Solar Probe and Solar Orbiter.