Authors: Antonio Niemela (KU Leuven), Nicolas Wijsen (KU Leuven), Luciano Rodriguez (Royal Observatory of Belgium), Angels Aran (Universitat de Barcelona , Jasmina Magdalenic (Royal Observatory of Belgium and KU Leuven) and Stefaan Poedts (KU Leuven)

In this work, we model the gradual solar energetic particle (SEP) event that was observed by near-Earth spacecraft in March and April 2013. Both events were modeled using PARADISE (PArticle Radiation Asset Directed at Interplanetary Space Exploration), which simulates the transport of SEPs through non-nominal solar wind configurations generated by the magnetohydrodynamic (MHD) model EUHFORIA (EUropean Heliospheric FOrecast Information Asset).

The simpler SEP event of April 11, 2013 started with a long-duration GOES M6.5 flare (peaked at 07:16 UT) that originated from NOAA active region 11719 situated at the moment of eruption at N09E12. It was associated with a CME with a projected line of the sight speed of about 800 km/s, observed by multiple spacecraft positioned in a broad range of heliolongitudes. The CME-driven shock generated by the event could have accelerated particles in the heliosphere. The Solar Dynamics Observatory (SDO) spacecraft registered, in many EUV channels, a high energetic flare associated with a halo CME and type II radio bursts. The CME was moderately fast but intense enough to generate an SEP event was registered by multiple spacecraft.

On the other hand, the March 15, 2013 event is much more complex. It starts with a long duration GOES M 1.1 X-ray flare was observed originating from the NOAA active region 11692 and with peak intensity registered at 06:58 UT. An Earth-directed asymmetric halo CME erupted from the Sun at 07:12UT, as seen by the coronagraphs aboard SOHO and STEREO. On March 16, the particle counts at L1 started increasing. A first sudden increase was registered, for energies up to 80 MeV, at around 20:00 UT and almost 6 hours after, the bulk of the particles arrived and the flux remained enhanced until the ICME ended on March 17, at around 06:00 UT.

In this work we present two different scenarios in which PARADISE was run. With this comparison we intend to showcase how the non-parker nature of the background solar wind affects the SEP propagation, and how accurately predicting preceding CMEs can improve the SEP prediction capabilities of the model.