Authors: F. Carcaboso (UMBC NASA GSFC), L.Y. Khoo (Princeton University), D. Lario (NASA GSFC), R. Gómez-Herrero (UAH), F. Espinosa Lara (UAH), I. Cernuda (UAH), E. Palmerio (PSI), D. Pacheco (USTC), G. Martín (UAH), B. Sánchez-Cano (University of Leicester), C. Lee (SSL UC Berkeley), A. Szabo (NASA GSFC), B. Lynch (SSL UC Berkeley), W. Wei (SSL UC Berkeley)

A series of solar energetic particle (SEP) events occurred in close succession between December 7 and December 10, 2024. The most significant of these originated from Active Region 3912, associated with an X2.3 class solar flare. These events were encountered by a constellation of spacecraft —Solar Orbiter (SolO; 0.9 au, -6° in longitude from Earth), BepiColombo (Bepi; 0.3 au, +5°), Earth-orbiting missions (~1 au), MAVEN (at Mars; 1.6 au, +22°), and STEREO-A (STA; 0.97 au, +28°)— which were immersed in diverse interplanetary solar wind conditions at that moment. Some of the events were not observed by all the spacecraft, while the most prominent was.

Notably, at Solar Orbiter, the most intense event showed a clear peak from the north-pointing telescope, observing ions exceeding 50 MeV and electrons above 7 MeV. The spacecraft was located within what appears to be a small-scale flux rope embedded in a Stream Interaction Region (SIR), while Wind at Earth’s L1, was found outside this structure at the onset of this event.

This study presents preliminary work focusing on the longitudinal distribution of these SEP events and the impact of large-scale interplanetary structures on their propagation. We will compare observations from various longitudinally separated spacecraft to investigate these aspects. Preliminary findings on the main event’s anisotropy, particularly its directional nature at Solar Orbiter and its relation to local structures, and the presence/absence of observations in the different spacecraft during the rest of the events underscore the importance of considering detailed interplanetary conditions for understanding SEP propagation and improving space weather prediction models.