Panel a: proton fluxes in the energy range within 10–20 MeVaa53169-24 measured by STEREO-B/LET from September 1– 15, 2014. Panel b: proton fluxes observed at Mercury by MESSEN- GER/FIPS instrument for the same date in the energy channel from 12.9 to 14 KeV (FIPS background counts in this energy channel can be caused by >1 MeV SEP electrons >10 MeV SEP protons; Gershman et al. 2015, 2016). Panel c: 15 keV 15 keV ion counts (which represent the background counts induced by SEP protons; Futaana et al. 2008) measured at Mars from September 1–15, 2014, by the IMA/ASPERA3 instrument on board Mars Express and HEND on Mars Odyssey in the energy range 195–>1000 keV (Sánchez–Cano et al. 2018). Panel d: proton fluxes measured by SOHO/ERNE instrument in the energy channel between 8 and 10 MeV, for the same time period. All the data plotted in panels a, b, and d were obtained from the AMDA database¹. Data plotted in panel (c) were retrieved from NASA’s Planetary Data System web page².