Observations of Low-Frequency Waves Excited by Newborn Interstellar Pickup He+ as Seen by the Ulysses Spacecraft

We report an analysis of low-frequency waves in the Ulysses magnetic field data that arise from newborn interstellar pickup He+. Ulysses observations of waves excited by interstellar H+ have already been reported, but in this analysis we identify waves due to the ionization of He atoms. While neutral He can reach inside 1 AU in significant numbers whereas interstellar neutral H cannot, we find that most of the waves due to He+ are seen at moderate to low heliolatitude beyond 3 AU. This may reflect the nature of the orbit where Ulysses spends a greater fraction of its time in this region, or it may reflect the turbulence conditions. Our analysis will address this and related questions.