%ADesai, M.%AMitchell, D.%AMcComas, D.%ADrake, J.%APhan, T.%ASzalay, J.%ARoelof, E.%AGiacalone, J.%AHill, M.%AChristian, E.%ASchwadron, N.%AMcNutt, R.%AWiedenbeck, M.%AJoyce, C.%ACohen, C.%ADavis, A.%AKrimigis, S.%ALeske, R.%AMatthaeus, W.%AMalandraki, O.%AMewaldt, R.%ALabrador, A.%AStone, E.%ABale, S.%AVerniero, J.%ARahmati, A.%AWhittlesey, P.%ALivi, R.%ALarson, D.%APulupa, M.%AMacDowall, R.%ANiehof, J.%AKasper, J.%AHorbury, T.%BJournal Name: The Astrophysical Journal; Journal Volume: 927; Journal Issue: 1 %D2022%I %JJournal Name: The Astrophysical Journal; Journal Volume: 927; Journal Issue: 1 %K %MOSTI ID: 10323919 %PMedium: X %TSuprathermal Ion Energy Spectra and Anisotropies near the Heliospheric Current Sheet Crossing Observed by the Parker Solar Probe during Encounter 7 %XAbstract We present observations of ≳10–100 keV nucleon −1 suprathermal (ST) H, He, O, and Fe ions associated with crossings of the heliospheric current sheet (HCS) at radial distances of <0.1 au from the Sun. Our key findings are as follows: (1) very few heavy ions are detected during the first full crossing, the heavy-ion intensities are reduced during the second partial crossing and peak just after the second crossing; (2) ion arrival times exhibit no velocity dispersion; (3) He pitch-angle distributions track the magnetic field polarity reversal and show up to ∼10:1 anti-sunward, field-aligned flows and beams closer to the HCS that become nearly isotropic farther from the HCS; (4) the He spectrum steepens either side of the HCS, and the He, O, and Fe spectra exhibit power laws of the form ∼ E −4 – E 6 ; and (5) maximum energies E X increase with the ion’s charge-to-mass ( Q / M ) ratio as E X / E H ∝ ( Q X / M X ) δ , where δ ∼ 0.65–0.76, assuming that the average Q states are similar to those measured in gradual and impulsive solar energetic particle events at 1 au. The absence of velocity dispersion in combination with strong field-aligned anisotropies closer to the HCS appears to rule out solar flares and near-Sun coronal-mass-ejection-driven shocks. These new observations present challenges not only for mechanisms that employ direct parallel electric fields and organize maximum energies according to E / Q but also for local diffusive and magnetic-reconnection-driven acceleration models. Reevaluation of our current understanding of the production and transport of energetic ions is necessary to understand this near-solar, current-sheet-associated population of ST ions. %0Journal Article