追踪AR 12975中磁通量绳足点：日冕暗化与数据驱动磁摩擦模拟

中文摘要 AI 辅助

日冕物质抛射（CMEs）由磁通量绳（MFRs）的爆发驱动，其足点通常通过日冕暗化区域间接观测。然而，由于探测方法和日冕磁场建模在爆发事件复杂性方面的局限性，观测到的暗化与真实MFR足点位置之间的关系仍不确定。我们旨在研究2022年3月28日AR 12975中的M4耀斑和CME事件，以确定观测到的日冕暗化在多大程度上追踪了爆发MFR的足点。我们还评估了这些特征与数据驱动磁摩擦模拟中MFR演化的比较。我们将多波长SDO/AIA观测与活动区的时间依赖数据驱动磁摩擦模拟相结合。我们使用强度阈值和最小强度图识别日冕暗化。对于具有挑战性的区域，我们使用了基于强梯度的定制区域增长算法。我们使用组合的扭转和挤压因子度量提取模拟中的MFR结构。我们比较了足点位置，并推导了来自暗化和模拟MFR的磁通量。模拟再现了观测到的MFR的形成、演化和爆发，其足点在爆发期间发生迁移。足点与暗化位置匹配良好。南部暗化显示出移动磁通量绳暗化的特征，而北部暗化表现为收缩磁通量绳暗化，并被耀斑带迅速闭合。面积和磁通量的定量比较显示模拟足点与观测暗化之间总体一致性良好，差异主要源于探测限制和事件复杂性。北部足点区域的暗化在观测中尤其具有挑战性，因为存在预先存在的低强度及其快速收缩。

英文摘要

Coronal mass ejections (CMEs) are driven by the eruption of magnetic flux ropes (MFRs) whose footpoints are often observed indirectly as coronal dimming regions. However, the relationship between observed dimmings and true MFR footpoint locations remains uncertain due to limitations in both detection methods and coronal magnetic field modelling caused by the complexity of eruptive events. We aim to investigate the M4 flare and CME event on 28 March 2022 in AR 12975 to determine how well observed coronal dimmings trace the footpoints of an erupting MFR. We also assess how these signatures compare with the MFR evolution from a data-driven magnetofrictional simulation. We combined multiwavelength SDO/AIA observations with a time-dependent data-driven magnetofrictional simulation of the AR. We identified coronal dimmings using intensity-thresholding and minimum-intensity maps. For challenging regions we used a tailored region growth algorithm from strong gradients. We extracted MFR structures in the simulation using a combined twist and squashing factor metric. We compared the location of the footpoints and derived magnetic fluxes from both dimmings and the modelled MFR. The simulation reproduces the formation, evolution, and eruption of the observed MFR whose footpoints migrate during the eruption. The footpoints match well with the dimming location. The southern dimming shows characteristics of a moving flux rope dimming, while the northern dimming behaves as a shrinking flux rope dimming that is rapidly closed by the flare ribbons. Quantitative comparisons of area and magnetic flux show good overall agreement between simulated footpoints and observed dimmings, with discrepancies mainly arising from detection limitations and event complexity. The dimmings at the northern footpoint region is particularly challenging in observations due to pre-existing low intensities and its fast shrinkage.

发表机构

• University of Helsinki（赫尔辛基大学）
• University of Graz, Institute of Physics（格拉茨大学物理研究所）
• University of Graz, Kanzelhöhe Observatory for Solar and Environmental Research（格拉茨大学坎泽勒霍厄太阳与环境研究天文台）
• NorthWest Research Associates（西北研究协会）

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补充信息

DOI

10.1051/0004-6361/202661790