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终端激波处的能量分配

Energy Partitioning at the Termination Shock

Judit Szente, Bart van der Holst, Gabor Toth, Merav Opher

arXiv 2609.05267首次发表:更新:

AI 中文总结

本研究通过改进的全球三维MHD模拟,将非绝热激波加热分配给冷质子、电子和PUIs,使终端激波温度跳变更符合V2观测,揭示PUIs在其中的关键作用,为相关模型提供了能量分配架构。

AI 中文摘要

我们展示了波士顿大学外日球层模型的全球三维磁流体动力学(MHD)模拟的新结果,在该模拟中,我们采用了一种新开发的方法,将非绝热激波加热分配给冷质子、电子和拾取离子(PUIs),同时保持所有离子(冷质子和PUIs)与电子的总能量守恒。在我们之前的模拟中(E.S. Bair等人,2025;B. van der Holst等人,2026),所有非绝热激波加热都被导向冷质子,导致终端激波(TS)处的热太阳风温度跳变过大。通过使用新方法,我们改进了模拟结果,使其更接近旅行者2号(V2)航天器观测到的TS处的温度跳变。我们的模拟接近V2测量的冷太阳风温度10至20倍的观测跳变条件,获得了相对于数据的模拟结果改进。由于我们以这种方式直接估算TS处非绝热加热的分布,因此有机会研究TS处冷等离子体和PUIs的加热物理过程。结果显示,TS处几乎100%的非绝热激波加热流向PUIs时,可再现沿V2轨迹观测到的跳变条件。该信息是理解塑造日球层的物理过程的关键。正如M. Opher等人(2020)所示,PUIs显著改变日球层的形状,例如,热PUIs的存在导致内日鞘收缩。我们的工作提供了动能模拟(J. Giacalone等人,2021)中激波处能量分配的架构,可用于全球MHD模型。

英文摘要

We show new results of a global 3D magnetohydrodynamic (MHD) simulation of the Boston University outer heliosphere model where we used a newly developed approach that distributes the non-adiabatic shock heating among the cold protons, electrons, and pickup-ions (PUIs), while maintaining total energy conservation of all ions (cold protons and PUIs) and electrons. In our previous simulations ( E.S. Bair et al. 2025; B. van der Holst et al. 2026), all non-adiabatic shock heating was channeled to the cold protons, resulting in a too large temperature jump at the termination shock (TS) for the thermal solar wind. Using a new methodology we improved the simulation results with respect to the temperature jump observed at the TS by Voyager 2 (V2) spacecraft. Our simulations approached the observed jump conditions of a factor 10--20 in the cold solar wind temperature V2 measurements, and we obtain improvements in the simulation results relative to the data. Because we directly estimate in this way the distribution of non-adiabatic heating at the TS, we have the opportunity to study the physical process of heating cold plasma and PUIs in the TS. The results show that having almost 100\% non-adiabatic shock heating going towards PUIs at the TS reproduces the jump conditions observed along the V2 trajectory. This information is key to understanding the physical processes that shape the heliosphere. As shown by M. Opher et al. (2020), PUIs significantly change the shape of the heliosphere, for example, the presence of hot PUIs results in a deflated inner heliosheath. Our work provides the architecture of how energy partitioning at shocks in kinetic simulations (J. Giacalone et al. 2021) can be utilized in global MHD models.

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