The Ulysses south polar pass: Transient fluxes of energetic ions

Using Ulysses low energy telescope (LET) measurements of protons and alpha particles with energies of ∼1–5 MeV/n, we present first observations of transient energetic particle events in the high latitude heliosphere. Three transient particle events with gradual onsets and time durations of several days have been identified in the LET data at heliographic latitudes as high as ∼60°S, at radial distances from the Sun between 3.3–3.6 AU. No transient increases were observed polewards of 60°S. All three of the events were associated with passage of a coronal mass ejection (CME) over Ulysses, and two were associated with the newly identified type of forward/reverse shock pairs in the solar wind caused by over‐expanding CMEs. The largest of the three transient events has also been observed at Earth's orbit, i.e. in the ecliptic. The observations show that energetic particles can be convected into the high latitude heliosphere through CMEs.