The high-energy proton instrument (HEPI), a compact Cherenkov radiation space weather monitorJoseph O’Neill, Fan Lei, Keith Ryden, Paul Morris, Ben Clewer, Fraser Baird, Paul Sellin, Clive Dyer, Melanie Heil, Piers Jiggens and Giovanni SantinJ. Space Weather Space Clim., 15 (2025) 27DOI: https://doi.org/10.1051/swsc/2025023
