Whitepaper #365 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: basic research. Additional topics: solar physics; space-based missions/projects; user-need-driven basic space weather research.
How ions are accelerated to extreme energies during solar eruptive events — solar flares and associated coronal mass ejections (CMEs) — is still not well understood. We recommend prioritizing new observations of ion-associated signatures through the funding of next-generation measurements primarily in gamma rays, as well as in energetic neutral atoms (ENAs), neutrons, and EUV.