Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields
Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields
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DOI：
10.1007/s11214-017-0354-8
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发表时间：
2016-12
影响因子：
10.3
通讯作者：
N. Pogorelov;H. Fichtner;A. Czechowski;A. Lazarian;B. Lembége;J. A. Roux;Marius Potgieter;K. Scherer;E. Stone;R. D. Strauss;T. Wiengarten;P. Wurz;G. Zank;Ming Zhang
中科院分区：
文献类型：
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作者：
N. Pogorelov;H. Fichtner;A. Czechowski;A. Lazarian;B. Lembége;J. A. Roux;Marius Potgieter;K. Scherer;E. Stone;R. D. Strauss;T. Wiengarten;P. Wurz;G. Zank;Ming Zhang
本文总结了由瑞士伯尔尼国际空间科学研究所（ISSI）资助的“日鞘过程和日层顶结构：模拟高能粒子、宇宙射线和磁场”小组所获得的结果。我们专注于物理过程发生在外部日光层，特别是在其边界称为日球顶，并在当地的星际介质。讨论了磁场、中性原子和离子之间的电荷交换以及太阳活动周期对日球顶拓扑结构和观测到的不同日球层间断的日心距离的重要性。结果表明，时间相关的，数据驱动的边界条件是必要的，以描述由theVoyager航天器探测到的日光层不对称性。我们还讨论了太阳层顶的结构，特别是由于它的不稳定性和磁重联。它表明，瑞利-泰勒不稳定性的鼻子的日球顶创建连续层的星际和日光层等离子体是磁连接到不同的源。这可能是旅行者1号在2012年夏天穿越日球顶结构约一个月时观测到的银河系和异常宇宙线通量突然变化的一种可能解释。本文还讨论了模拟结果与现场和遥测观测数据的拟合问题。本文结合航海家号的观测结果讨论了日球顶附近的磁场分布。有人认为，一个经典的日光层电流片形成由于太阳的旋转是没有观察到的原位测量，不应该被期望存在于数值模拟延伸到日光层的边界。此外，我们讨论了内，外日鞘中的高能粒子的运输，集中在各向异性的空间扩散扩散张量和垂直扩散的俯仰角依赖性，并证明后者可以解释观测到的俯仰角各向异性的异常和银河宇宙射线在外日鞘。
This paper summarizes the results obtained by the team “Heliosheath Processes and the Structure of the Heliopause: Modeling Energetic Particles, Cosmic Rays, and Magnetic Fields” supported by the International Space Science Institute (ISSI) in Bern, Switzerland. We focus on the physical processes occurring in the outer heliosphere, especially at its boundary called the heliopause, and in the local interstellar medium. The importance of magnetic field, charge exchange between neutral atoms and ions, and solar cycle on the heliopause topology and observed heliocentric distances to different heliospheric discontinuities are discussed. It is shown that time-dependent, data-driven boundary conditions are necessary to describe the heliospheric asymmetries detected by theVoyagerspacecraft. We also discuss the structure of the heliopause, especially due to its instability and magnetic reconnection. It is demonstrated that the Rayleigh–Taylor instability of the nose of the heliopause creates consecutive layers of the interstellar and heliospheric plasma which are magnetically connected to different sources. This may be a possible explanation of abrupt changes in the galactic and anomalous cosmic ray fluxes observed byVoyager 1when it was crossing the heliopause structure for a period of about one month in the summer of 2012. This paper also discusses the plausibility of fitting simulation results to a number of observational data sets obtained byin situand remote measurements. The distribution of magnetic field in the vicinity of the heliopause is discussed in the context ofVoyagermeasurements. It is argued that a classical heliospheric current sheet formed due to the Sun’s rotation is not observed byin situmeasurements and should not be expected to exist in numerical simulations extending to the boundary of the heliosphere. Furthermore, we discuss the transport of energetic particles in the inner and outer heliosheath, concentrating on the anisotropic spatial diffusion diffusion tensor and the pitch-angle dependence of perpendicular diffusion and demonstrate that the latter can explain the observed pitch-angle anisotropies of both the anomalous and galactic cosmic rays in the outer heliosheath.