标题： 理解IBEX带状结构使用拾取质子输运的动能模型在无散射极限下 显示英文标题

标题： Understanding the IBEX ribbon using the kinetic model of pickup proton transport in a scatter-free limit

摘要： IBEX的一项最引人注目的发现是带状区域——在天空中观测到的一条增强的ENA通量狭窄带。主流解释认为IBEX带状区域是由次级ENA机制引起的。在这个过程中，通过太阳风（SW）质子与日球层内的星际H原子之间的电荷交换产生的初级H ENA，穿过日球边界的HP，并与LISM中的质子进一步发生电荷交换，产生拾取质子。其中一些拾取质子随后与星际H原子发生电荷交换，形成次级ENA，其中一些再次向太阳方向运动并被IBEX探测到。本文介绍了一种开发的动能模型，用于模拟次级ENA通量。使用从SW/LISM相互作用的动能-磁流体力学模型中得出的日球层等离子体和H原子的全球分布来执行带状区域模拟。该模型考虑了所有相关的初级ENA群体，包括中性的热太阳风质子、中性的拾取质子以及起源于内日球层边界（IHS）的ENA。拾取质子穿越HP的传输由无散射极限下的各向异性速度分布的聚焦传输方程描述，假设没有俯仰角散射或能量扩散。我们的模拟定性地再现了IBEX-Hi带状区域的观测结果，并在低日纬度处表现出良好的定量一致性。然而，该模型低估了高日纬度处的通量，这可能是因为忽略了这项工作中使用的静态框架中非稳定状态的SW行为。研究强调了IHS中的ENA的重要性，这是首次在日球层中拾取质子传输的动能模型框架中考虑的，对于准确再现IBEX-Hi在最高能量步骤上观测到的带状区域通量至关重要。 显示英文摘要

摘要： One of the most remarkable discoveries by the IBEX is the ribbon - a narrow band of enhanced ENA fluxes observed in the sky. The prevailing explanation attributes the IBEX ribbon to the secondary ENA mechanism. In this process, primary H ENAs, produced via charge exchange between solar wind (SW) protons and interstellar H atoms within the heliosphere, travel beyond the heliopause (HP) and undergo further charge exchange with protons of the LISM, generating pickup protons. Some of these pickup protons subsequently experience charge exchange with interstellar H atoms, forming secondary ENAs, some of which travel back toward the Sun and are detected by the IBEX. This paper presents a kinetic model developed to simulate secondary ENA fluxes. Ribbon simulations are performed using global distributions of plasma and H atoms in the heliosphere derived from a kinetic-MHD model of the SW/LISM interaction. The model accounts for all relevant primary ENA populations, including neutralized thermal SW protons, neutralized pickup protons, and ENAs originating in the inner heliosheath (IHS). The transport of pickup protons beyond the HP is described by the focused transport equation for a gyrotropic velocity distribution in the scatter-free limit, assuming no pitch-angle scattering or energy diffusion. Our simulations qualitatively reproduce IBEX-Hi ribbon observations and exhibit good quantitative agreement at low heliolatitudes. However, the model underestimates fluxes at high heliolatitudes, likely due to the omission of non-stationary SW behavior in the stationary framework used in this work. The study highlights the importance of ENAs from the IHS, a population considered for the ribbon production in the frame of the kinetic model of pickup proton transport in the heliosphere for the first time, for accurately reproducing ribbon fluxes observed by IBEX-Hi at the highest energy steps.