日球层中的分岔：全球尺度日球伪流演化与次级日球电流片的形成
Bifurcations in the Heliosphere: Global-scale Coronal Pseudostreamer Evolution and the Creation of Secondary Heliospheric Current Sheets
- University of California–Los Angeles（加州大学洛杉矶分校）
- Univ Toulouse, CNES, CNRS, IRAP（图卢兹大学、法国国家空间研究中心、法国国家科学研究中心、图卢兹天体物理研究所）
- Advanced Heliophysics（高级日球物理学）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
研究人员通过PLUTO MHD代码模拟，揭示偶极与四极场强度近似相等时，日冕可在单、双日球电流片构型间振荡，形成次级电流片，为太阳周演化提供了新见解。
中文摘要 AI 辅助
日球电流片（HCS）是太阳风中极性相反的开放磁场之间的边界，这些磁场连接至日球中各自的开放通量区域。HCS常被描述为一个盘状片，其受太阳磁赤道倾角、太阳自转与太阳风膨胀的共同作用而发生扭曲，它是盔状流带的延伸——盔状流带是观测到的光球磁场全球偶极分量产生的闭合通量区域。在缺乏强偶极场时，主导的四极场可产生两个独立的HCS。本文利用WindPredict-AW PLUTO磁流体动力学（MHD）代码，开展了一组理想化的轴对称太阳风模拟，旨在研究单HCS日冕与内日球层向多HCS构型的转变。我们系统改变全球场中偶极/四极分量的相对强度，发现这会形成一个大尺度闭合通量伪流，其会与环境太阳风相互作用；当日极与四极的大小近似相等时，我们的模型日冕可在数日至数周的时间尺度上在单HCS与双HCS构型之间振荡。我们表征了全球尺度伪流向局部次级盔状流带转变的等离子体动力学，该次级盔状流带带有自身的HCS，环绕着新开放的极性相反的日冕洞。我们讨论了这些结果对太阳周演化以及高度结构化日冕与内日球层动态耦合的意义。
英文摘要
The heliospheric current sheet (HCS) is the boundary between open magnetic fields of opposite polarity in the solar wind that connect back to their respective open flux regions in the corona. The HCS is often described as a disc-like sheet warped by the combined effects of the inclination of the magnetic equator on the Sun, solar rotation, and solar wind expansion. The HCS is an extension of the helmet streamer belt-the closed-flux region resulting from the global dipole component of the observed photospheric magnetic field. In the absence of a strong dipole, a dominant quadrupole can result in two separate HCSs. Here we report on a set of idealized, axisymmetric solar wind simulations designed to study the transition of the single-HCS corona and inner heliosphere into a multiple-HCS configuration, run with the WindPredict-AW PLUTO MHD code. We systematically vary the relative strengths of the dipole/quadrupole contributions to the global field and show this results in the formation of a large-scale, closed-flux pseudostreamer that interacts with the ambient solar wind. We find that when the dipole and quadrupole magnitudes are approximately equal, our model corona can oscillate between a one- and two-HCS configuration on the timescale of days-to-weeks. We characterize the plasma dynamics of the transition of a global-scale pseudostreamer into a localized, secondary helmet-streamer belt with its own HCS surrounding a newly-opened, opposite-polarity coronal hole. We discuss the implications of our results for solar cycle evolution and the dynamic coupling of the highly structured corona and inner heliosphere.
