Authors: L. Y. Khoo (Princeton University)

Energy spectra of solar energetic particles (SEP) carry valuable information about the acceleration and propagation processes of energetic particles. Typically, these spectra exhibit a steepening at higher energies either in the form of a broken power law or an exponential rollover. Recent studies have reported that lower-energy (<1 MeV) ions exhibit a flat energy spectrum over >12 hours before a shock arrival. On 16 February 2022, Parker Solar Probe reported measurements of such a prolonged period of a flat-energy spectrum (<1 MeV protons) at 0.35 au. This may represent the closest of such observations to the Sun thus far. In this study, we use the latest dataset from PSP/EPI-Hi, which is based on updated geometric factors, to investigate the evolution of the energy spectrum for higher energy (>1 MeV) protons during this event. This work presents a detailed spectral analysis in the context of an interplanetary coronal mass ejection (ICME) crossing and explores its relationship with different substructures found during the crossing.