SEPSTER3D

SEPSTER3D is an empirical model that predicts solar energetic particle (SEP) proton peak intensities and event-integrated fluences at Mars. It extends SEPSTER2D from 1 AU to Mars by using the parent CME speed and direction, the Mars magnetic connection calculated with a Parker-spiral model referenced to 2.5 solar radii, and an energy-dependent 1-AU-to-Mars intensity scaling.

Predictions are issued only for parent CMEs with speed >=600 km/s and half-width >=20 deg, corresponding to the approximate validity range of the empirical model. SEPSTER3D is currently constrained by a limited multi-spacecraft event sample. The parent SEPSTER2D spectral model is best constrained in the tens-of-MeV range; higher-energy predictions and integral quantities increasingly depend on spectral extrapolation. The 10-GeV upper bound is used for numerical integration and should not be interpreted as a claim of differential-model validation to 10 GeV.

CME speed, direction, half-width, and first-appearance time from the DONKI CME catalog; solar-wind speed at Mars from operational WSA-ENLIL output; Mars heliographic Stonyhurst coordinates calculated internally using SunPy/Astropy.

Differential proton SEP peak intensities and event-integrated fluences at 10, 30, 50, 100, and 500 MeV, together with corresponding energy-integrated (>E) quantities, uncertainties, and peak-time estimates. The internal spectrum is evaluated from 10 MeV to 10 GeV to calculate the integral quantities.

Initial SEPSTER3D v0.1. Mars-only extension of SEPSTER2D, adding Mars ephemeris, WSA-ENLIL solar-wind speed at Mars, Parker-spiral magnetic connectivity, and energy-dependent scaling of the SEP intensity from 1 AU to Mars.