The transport of Solar Energetic Particles (SEPs) through the interplanetary space remains a chal-
lenging aspect in space physics. The effects of the interplanetary magnetic field and solar wind
turbulence on the SEP arrival to Earth has motivated the adoption of physics-based approaches
in operational space weather forecasting. 3D physics-based models offer a framework for incor-
porating the complexity of SEP transport mechanisms. The forecasting tool, SPARX (Marsh et
al. (2015)), employs a relativistic full-orbit test particle approach to simulate SEP propagation to
predict their arrival and help assess the potential hazard they may cause. Detection of a solar flare
with a magnitude > M1.0 triggers the SPARX system to produce synthetic particle flux profiles
from a database of SEP simulations to forecast observations that would be made at 1AU by a
spacecraft.

To enhance SPARX’s modeling capabilities, we focus here on validating the model through a
systematic analysis of recent SEP events. The performance evaluation methodology implemented
in Dalla et al. (2018) used a comprehensive list of X-class solar flares between 1997 and 2017
where for every flare, SPARX was operated in forecast mode. The outputs were analysed for SEP
event prediction and performance metrics such as Probability of Detection (POD), False Alarm
Ratio (FAR) and Critical Success Index (CSI) were calculated. This evaluation methodology will
be adapted for events post 2017 to incorporate a larger dataset and thereby enabling a statistically
robust validation of the tool. We chose a proton energy threshold of > 20 MeV for maintaining
consistency for model evaluation. We present preliminary analysis of SPARX-generated synthetic
SEP flux profiles against multi-spacecraft observations from SOLO, SOHO, and STEREO-A,
assessing its current efficiency in reproducing key event characteristics such as onset times and
intensity profiles. We discuss how these findings guide next-stage improvements in SPARX.
This work aims to contribute to bridging the gap between 3D physics-based SEP modeling and
real-time forecasting, ultimately advancing our capability to assess and mitigate SEP-driven space
weather hazards. Future enhancement consists of incorporating cross-field transport of SEPs and
evaluating its impact on SPARX’s forecasting accuracy.