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arXiv 2412.03211astro-ph.SR
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宁静太阳埃勒曼炸弹的磁拓扑及其相关的紫外增亮

Magnetic Topology of quiet-Sun Ellerman bombs and associated Ultraviolet brightenings

Aditi Bhatnagar, Avijeet Prasad, Luc Rouppe van der Voort, Daniel Nóbrega-Siverio, Jayant Joshi

AI总结:

本研究利用SST和IRIS数据,通过势场外推和k-means聚类,揭示了宁静太阳埃勒曼炸弹与紫外增亮相关的四种磁拓扑,其中扇-脊拓扑含3D零点,能量释放为10^23至10^24尔格。

摘要:

宁静太阳埃勒曼炸弹(QSEBs)是宁静太阳低层大气中的小尺度磁重联事件。近期研究表明,其中一小部分可以与过渡区中的紫外(UV)增亮在空间和时间上同时发生。我们旨在理解与紧密发生的QSEBs和UV增亮相关的磁拓扑如何促进能量输运并将这些事件联系起来。我们使用了来自瑞典1米太阳望远镜(SST)的高分辨率H-beta观测数据,并通过k-means聚类检测QSEBs。我们利用光球层Fe I 6173埃线的光谱偏振数据,通过势场外推获得了磁场拓扑。为了检测UV增亮,我们使用了来自界面区域成像光谱仪(IRIS)的协调且共对准的数据,并在(IRIS)1400埃狭缝焦平面图像通道上施加了高于中值背景5倍标准差的阈值。我们识别出四种不同的磁构型将QSEBs与UV增亮联系起来,包括简单的偶极构型和具有三维(3D)磁零点且更为复杂的扇-脊拓扑。在扇-脊拓扑中,UV增亮发生在3D零点附近,而QSEBs则可以在外脊、内脊和扇面的足点附近找到。我们发现3D零点的高度在0.2兆米到2.6兆米之间变化,这取决于该区域的磁场强度。我们注意到,一些QSEBs和UV增亮虽然彼此靠近发生,但并未通过同一重联过程在拓扑上相连。我们发现QSEBs期间释放的能量范围在10^23到10^24尔格之间。这项研究表明,磁连通性和拓扑特征(如3D零点)对于将低层大气中的QSEBs与过渡区中的UV增亮联系起来至关重要。

英文摘要:

Quiet-Sun Ellerman bombs (QSEBs) are small-scale magnetic reconnection events in the lower atmosphere of the quiet Sun. Recent work has shown that a small percentage of them can occur co-spatially and co-temporally to ultraviolet (UV) brightenings in the transition region. We aim to understand how the magnetic topologies associated with closely occurring QSEBs and UV brightenings can facilitate energy transport and connect these events. We used high-resolution H-beta observations from the Swedish 1-m Solar Telescope (SST) and detected QSEBs using k-means clustering. We obtained the magnetic field topology from potential field extrapolations using spectro-polarimetric data in the photospheric Fe I 6173 A line. To detect UV brightenings, we used coordinated and co-aligned data from the Interface Region Imaging Spectrograph (IRIS) and imposed a threshold of 5 sigma above the median background on the (IRIS) 1400 A slit-jaw image channel. We identify four distinct magnetic configurations that associate QSEBs with UV brightenings, including a simple dipole configuration and more complex fan-spine topologies with a three-dimensional (3D) magnetic null point. In the fan-spine topology, the UV brightenings occur near the 3D null point, while QSEBs can be found close to the footpoints of the outer spine, the inner spine, and the fan surface. We find that the height of the 3D null varies between 0.2 Mm to 2.6 Mm, depending on the magnetic field strength in the region. We note that some QSEBs and UV brightenings, though occurring close to each other, are not topologically connected with the same reconnection process. We find that the energy released during QSEBs falls in the range of 10^23 to 10^24 ergs. This study shows that magnetic connectivity and topological features, like 3D null points, are crucial in linking QSEBs in the lower atmosphere with UV brightenings in the transition region.

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