日冕物质抛射在太阳日冕中的三维磁场结构
On the 3D Magnetic Structure of Coronal Mass Ejections Through the Solar Corona
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- Predictive Science Inc.（预测科学公司）
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中文总结 AI 辅助
本文通过合成航天器舰队模拟理想化日冕物质抛射，发现采样位置显著影响从就地测量推断的磁通量绳三维结构，并提出了源区拓扑的可能就地指标。
中文摘要 AI 辅助
日冕物质抛射（CME）内部结构中的磁场被认为以磁通量绳的形式组织，该结构由缠绕在中心轴周围的扭曲磁场组成。对CME的遥感观测显示出广泛的形态、动力学和演化，包括旋转、非均匀膨胀、偏转以及与周围太阳风的相互作用。然而，就地测量通常仅通过一个（或至多几个）一维航天器轨迹穿过一个大型三维结构，这限制了我们在空间和时间上确定CME磁场结构变化的能力。在本工作中，我们使用球外磁流体动力学算法（Magnetohydrodynamic Algorithm Outside a Sphere）代码，分析了两个理想化CME在1-30太阳半径（$R_{\odot}$）范围内早期演化过程中的磁场构型。初始磁通量绳仅在其相对于全球偶极子的方向上有所不同，并在简化的日冕环境中从流带下方的双极活动区爆发。我们在CME路径上部署了多个合成航天器，它们位于不同的纬度、经度和日心距离组合处。我们在合成就地剖面中识别并检查磁通量绳特征，以表征径向变化以及纬度/经度变化。我们发现，即使在太阳极小期类似条件下爆发的简化CME中，采样位置也会显著影响通过常用于就地测量的磁通量绳重建和分析技术所推断出的全局结构。此外，我们考虑了可能作为源区拓扑结构指标的就地特征。
英文摘要
The magnetic fields that make up the internal structure of coronal mass ejections (CMEs) are thought to be organised in a flux rope configuration, consisting of twisted magnetic fields that wind about a central axis. Remote-sensing observations of CMEs show a wide range of morphologies, dynamics, and evolution, including rotation, non-uniform expansion, deflection, and interaction with the ambient solar wind. In-situ measurements, however, typically consist of a single 1D spacecraft trajectory through a large 3D structure (or few at best), restricting our ability to determine how CME magnetic structure varies in space and time. In this work, we analyse the magnetic configuration of two idealised CMEs during their early evolution in the range 1-30 $R_{\odot}$ using the Magnetohydrodynamic Algorithm Outside a Sphere code. The initial flux ropes differ only in their orientation with respect to the global dipole and erupt from a bipolar active region below the streamer belt in a simplified coronal environment. We deploy a fleet of synthetic spacecraft throughout the CMEs' paths at different combinations of latitudes, longitudes, and heliocentric distances. We identify and examine flux rope signatures in the synthetic in-situ profiles to characterise radial variations as well as latitudinal/longitudinal ones. We find that, even in a simplified CME erupting under solar minimum-like conditions, the sampling location significantly affects the global structure that would be deduced from common flux rope reconstruction and analysis techniques used for in-situ measurements. Additionally, we consider possible in-situ signatures that may serve as indicators of the source region's topology.
