Interstellar proton energy spectrum by Burger et al. (2000; dotted line) with our best prediction of the cosmic-ray proton energy spectrum in February 2023 (thick continuous line, ϕ = 650 MV c⁻¹). The modulated proton spectra obtained by assuming a solar modulation parameter of 300 MV c⁻¹ (dot-dot-dot-dashed line), 500 MV c⁻¹ (dot-dashed line) and 800 MV c⁻¹ (dot-dot-dashed line) are shown for comparison. The solid stars (crosses) indicate the GCR (SEP) proton measurements carried out on February 22 (25), 2023 by the EPD/HET experiment. The tight line represents the PAMELA experiment observations during the decay phase of a weak SEP event dated December 14, 2006.