In this study, we extend the prior interstellar pickup ion (PUI) observations from the Solar Wind Around Pluto (SWAP) instrument on New Horizons out to nearly 47 au—essentially halfway to the termination shock in the upwind direction. We also provide significantly improved analyses of these and prior observations, including incorporating a cooling index, α, to characterize the nonadiabatic heating of PUI distributions. We find that the vast majority (93.6%) of all distributions show additional heating above adiabatic cooling. Speed jumps indicate compressional waves and shocks with associated enhancements in core solar wind and PUI densities and temperatures. Interestingly, additional heating of the PUIs as indicated by a peak in the cooling index follows the jumps by about a week. We characterize nearly continuous solar wind and H⁺ PUI data over ∼22–47 au, producing radial gradients, “fiducial” values at 45 au—halfway to the nominal upstream termination shock—for direct comparison to models, and extrapolated values at the shock. These termination shock values are n _PUI = (4.1 0.6) 10⁻⁴ cm⁻³, T _PUI = (5.0 0.4) 10⁶ K, P _PUI = 30 4 fPa, α = 2.9 0.2, n _PUI/n _Total = 0.24 0.02, T _PUI/T _SW = 716 124, P _PUI/P _SW = 173 32, P _PUI/P _{SW − Dyn} = 0.14 0.01. The PUI thermal pressure exceeds by more than an order of magnitude the thermal solar wind and magnetic pressures in the outer heliosphere. SWAP provides the first and only direct observations of interstellar PUIs in the outer heliosphere, which are critical for both inferring the plasma conditions at the termination shock and understanding PUI-mediated shocks in general. This study examines these observations and serves as the citable reference for these critical data.

在这项研究中，我们将新视野号上冥王星周围太阳风 (SWAP) 仪器的先前星际拾取离子 (PUI) 观测扩展到近 47 au——基本上是逆风方向终止激波的一半。我们还提供了对这些和先前观察结果的显着改进的分析，包括结合冷却指数α，表征 PUI 分布的非绝热加热。我们发现所有分布中的绝大多数 (93.6%) 显示出高于绝热冷却的额外加热。速度跳跃表明压缩波和冲击与核心太阳风和 PUI 密度和温度的相关增强。有趣的是，冷却指数的峰值表明 PUI 的额外加热跟随跳跃大约一周。我们描述了大约22-47 au 范围内几乎连续的太阳风和 H ⁺ PUI 数据，产生径向梯度，45 au 处的“基准”值——标称上游终止冲击的一半——用于与模型直接比较，以及冲击时的外推值. 这些终端冲击值为n _PUI = (4.1 0.6) 10 ^-4 cm^-3，Ť _PUI =（5.0 0.4）10 ⁶ K，P _PUI = 30 4 FPA，α = 2.9 0.2，Ñ _PUI / Ñ _总= 0.24 0.02，Ť _PUI / Ť _SW = 716 124，P _PUI / P _SW = 173 32, P _PUI / P _{SW − Dyn}= 0.14 0.01。PUI 热压超过外日光层中的太阳热风和磁压一个数量级以上。SWAP 提供了第一次也是唯一一次对外日光层中星际 PUI 的直接观测，这对于推断终止激波时的等离子体条件和了解 PUI 介导的一般激波都至关重要。本研究检查了这些观察结果，并作为这些关键数据的可引用参考。