Exploring the Structure of the Local Interstellar Medium with the Interstellar Boundary Explorer (IBEX)

该项目的目标是对最近提出的解释高能中性原子（ENAs）增强微分通量的所谓带状模型进行全面的定量评估。根据这一模型，用星际边界探测器（IBEX）航天器在全天空ENA通量图中检测到的带状物是所谓的H波的结果，即从ISM传播到日光层的中性氢数密度的局部增强。随着旅行者1号航天器最近进入星际空间，由于有机会对本地星际介质进行现场测量，有关的研究将从三个方面促进当代关于外部日光层和本地星际介质的研究：首先，该研究将有助于澄清IBEX带的性质。其次，它将限制局部ISM的物理性质（如星际磁场的方向和中性密度变化）。第三，它将大大提高我们对太阳风与星际环境相互作用的理解。该项目的主要目标是回答以下三个关键科学问题：（Q1）日鞘内质子速度分布对ENA谱的影响是什么？(Q2)增强的差分ENA通量带是如何在自洽模拟的“现实”日光层中形成的？（Q3）中性气体在本星际介质中扰动的性质是什么？这些目标意味着相应的任务，即（T1）计算ENA种子种群，即质子的速度分布，（T2）使用模拟日光层计算来自带状物的微分ENA通量，以及（T3）确定星际中性气体中扰动的性质。 通过完成这些任务来实现项目的目标，我们不仅将对有关最遥远的现场探索前沿的当代研究做出上述三方面的贡献，而且还将通过限制当地ISM的状态和结构，帮助将日光层物理学和天体物理学之间始终存在的概念联系转化为实际的物理联系，其可以被认为是一般ISM的代表。

The goal of this project is a comprehensive quantitative assessment of a recently proposed model explaining the so-called ribbon of enhanced differential fluxes of energetic neutral atoms (ENAs). According to this model the ribbon, that was detected in the all-sky ENA flux maps with the Interstellar Boundary Explorer (IBEX) spacecraft, is a consequence of a so-called H-wave, i.e. a localized enhancement of the neutral hydrogen number density that is propagating from the ISM into the heliosphere. The corresponding study will contribute in a threefold way to the contemporary research regarding the outer heliosphere and the local interstellar medium (ISM) that -- with the recent entry of the Voyager~1 spacecraft into interstellar space -- received renewed attention due to the opportunity to make in situ measurements of the ISM: First, the study will contribute to clarify the nature of the IBEX ribbon. Second, it will constrain physical properties of the local ISM (such as the orientation of the interstellar magnetic field and neutral density variations). And, third, it will significantly improve our understanding of the interaction of the solar wind with its interstellar environment.The main objectives of the project is the answering of the following three scientific key questions: (Q1) What is the influence of the inner-heliosheath proton velocity distribution on the ENA spectra?, (Q2) How does the ribbon of enhanced differential ENA fluxes form in a self-consistently simulated 'realistic' heliosphere?, and (Q3) What are the properties of disturbances of the neutral gas in the local interstellar medium? These objectives imply corresponding tasks, namely (T1) the computation of the velocity distribution of the ENA seed population, i.e. protons, (T2) the computation of the differential ENA fluxes from the ribbon using a simulated heliosphere, and (T3) the determination the properties of disturbances in the interstellar neutral gas. With achieving the goal of the project by the completion of these tasks, we will not only make the mentioned threefold contribution to the contemporary research regarding the most distant frontier of in situ exploration, but help to transform the always existing conceptual link between heliospheric physics and astrophysics into an actual physical link by constraining the state and structure of the local ISM, which can be considered as representative for the general ISM.