Galactic Helium Spectrum Approaching the Minimum of Solar Cycle 24 Measured by the High-Energy Particle Detector (HEPD-01)

This is the authors' abstract. We don't add key points for this paper.

The High-Energy Particle Detector (HEPD-01) is one of the payloads on board the China Seismo-Electromagnetic Satellite (CSES-01), launched in 2018 February. The detector is a light and compact instrument, well suited for precise measurements of proton and helium fluxes in the energy range from a few tens to a few hundreds of MeV n −1 . As is well established, the energy spectra of Galactic cosmic rays (GCRs) carry fundamental information about their origin and propagation. However, when observed near Earth, they are significantly affected by the solar wind and its embedded magnetic field. In this work, we present the first spectra of Galactic helium nuclei near the minimum of solar cycle 24 in the low-energy interval between 50 and 200 MeV n −1 —a region scarcely accessed by currently active low-Earth-orbit spaceborne instruments. Additionally, the p/He ratio is shown as a function of energy. Finally, comparisons with the most up-to-date numerical and Monte Carlo models are performed and discussed.