1,1,1,1,8,1,- 1Kiel University, Institut für Experimentelle und Angewandte Physik, Physik, Kiel, Germany
- 2School of Earth and Space Sciences, University of Science and Technology of China, Hefei, PR China
- 3CAS Center for Excellence in Comparative Planetology, USTC, Hefei, PR China
- 4Planetary Science Division, Southwest Research Institute, Boulder, CO, USA
- 5Leidos Corporation, Houston, TX, USA
- 6German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
- 7Deep Space Exploration Laboratory/School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
- 8Space Sciences Laboratory, University of California Berkeley, Berkeley, CA, USA
On 9 October 2024, a major Solar Energetic Particle (SEP) event was detected simultaneously across a wide range of heliolongitudes and heliocentric distances. Signatures were observed by Solar Orbiter, Parker Solar Probe (PSP), STEREO-A, near-Earth spacecraft (SOHO, GOES, ACE), and surface instruments on Mars (MSL/RAD). The event originated from an X1.8 solar flare in Active Region (AR) 3848, which produced a fast, Earth-directed full-halo coronal mass ejection (CME). This study aims to characterize the acceleration and heliospheric distribution of SEPs during this event and to evaluate its implications for space weather forecasting and radiation risks for future human exploration of Mars. We combined imaging and in situ particle observations from multiple spacecraft positioned at different longitudes and heliocentric distances. Analyses included flare and CME timing, SEP fluxes, onset times, and energy spectra at each vantage point. Multi-point comparisons allowed us to assess how CME-driven shocks accelerate and transport SEPs, and how cross-field propagation and interplanetary scattering shaped the observed particle distributions, particularly at Mars.
The X1.8 flare began at 01:25 UTC, peaked at 01:56 UTC, and ended at 02:43 UTC. The associated full-halo CME was first detected by LASCO at 02:12 UTC from ~N13 W08, with speeds estimated at ~1,500 km/s (leading edge) and ~2,100 km/s (shock front). The CME arrived at Earth around 10 October 14:45 UTC. Solar proton intensities began rising at 02:40 UTC and reached S2 (moderate) radiation storm levels by 07:30 UTC. Widespread SEP detections, including at Mars, demonstrate efficient particle acceleration over an exceptionally broad spatial domain and highlight the role of extended shock fronts, cross-field diffusion, and interplanetary turbulence in shaping SEP propagation. These results provide critical constraints for SEP transport models and underline the value of multi-point observations for advancing forecasting capabilities and mitigating radiation hazards in deep space missions.
How to cite: Khaksari, S., Wimmer-Schweingruber, R. F., Löwe, J. L., Guo, J., Pacheco, D., Heber, B., Dröge, H., J. Lillis, R., Ding, Z., Ehresmann, B., M. Hassler, D., Löffler, S., Zeitlin, C., and Matthiä, D.: Requirements for Solar Energetic Particle Forecasting at Mars: Lessons from Multi-Point Observations of the 9 October 2024 CME-Driven Shock, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10464, https://doi.org/10.5194/egusphere-egu26-10464, 2026.
