Upstream and magnetosheath energetic ions with energies to ≈2 MeV

We present the first observations of ≈2 MeV ion bursts detected in the upstream region and the magnetosheath by the three‐dimensional (3D) plasma and energetic particles instrument on the WIND spacecraft. This instrument measures the full 3D distribution of particles from a few eV to several MeV, and allows characterization of the upstream ions in both pitch angle and energy. The new feature observed is the presence of bursts of ions at energies extending up to ≈2 MeV, both upstream and in the magnetosheath. The observation of MeV ions has strong implications for the ion source and acceleration mechanisms.