- 1European Space Agency, European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
- 2Universidad de Alcalá, Space Research Group (SRG-UAH), Plaza de San Diego s/n, 28801 Alcalá de Henares, Madrid, Spain
- 3Predictive Science Inc., San Diego, CA 92121, USA
- 4European Space Agency, European Space Research and Technology Centre (ESTEC), 2201 AZ Noordwijk, The Netherlands
- 5Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
- 6California Institute of Technology, Pasadena, CA 91125, USA
- 7Laboratory for Instrumentation and Experimental Particle Physics (LIP), Complexo Interdisciplinar Av. Prof. Gama Pinto, n.2, 1649-003 Lisboa, Portugal
JUICE was launched in April 2023, and it is now in its cruise phase to Jupiter, where it is scheduled to arrive in July 2031. JUICE carries a radiation monitor, namely the RADiation hard Electron Monitor (RADEM) to measure protons, electrons, and ions, detecting particles coming from the anti-Sun direction. On 2024 May 13, a large solar energetic particle (SEP) event took place in association with an eruption close to the western limb of the Sun as seen from Earth. Providentially, at that time JUICE was very closely located to STEREO-A, namely the difference in location was 0.13 au in radial distance, 0.3° in latitude, and 1.6° in longitude.
We analysed the interplanetary context through which the particles propagated using the ENLIL model combined with in-situ plasma measurements. We studied the proton anisotropies measured by near-Earth spacecraft and STEREO-A and focused on an isotropic period during the decay phase of the SEP event to compute the proton energy spectrum. We fit the STEREO-A spectrum and compared it to that measured by JUICE to estimate energy-dependent intercalibration factors.
The proton spectral indices measured by JUICE and STEREO-A were similar. The proton fluxes measured at the effective energy channels of 6.8 MeV, 22.2 MeV, and 31.6 MeV by the radiation monitor onboard JUICE agree within 15% with the STEREO-A measurements. The differences were slightly higher for the 14.0 MeV channel, which agrees within 30%.
How to cite: Rodríguez-García, L., Palmerio, E., Pinto, M., Dresing, N., Cohen, C., Gómez-Herrero, R., Gieseler, J., Santos, F., Espinosa Lara, F., Cernuda, I., Witasse, O., and Altobelli, N.: Comparing observations of the closely located JUICE and STEREO-A spacecraft during the widespread solar energetic particle event of 2024 May 13, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6498, https://doi.org/10.5194/egusphere-egu25-6498, 2025.
