High-resolution Observations of Small-scale Flux Emergence by GST
High-resolution Observations of Small-scale Flux Emergence by GST
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DOI：
10.3847/1538-4357/aba696
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发表时间：
2020-09
期刊：
影响因子：
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通讯作者：
Jiasheng Wang;Chang Liu;W. Cao;Haimin Wang
中科院分区：
文献类型：
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作者：
Jiasheng Wang;Chang Liu;W. Cao;Haimin Wang
最近的观测表明，新兴的通量区，构成了太阳活动区的早期阶段，包括大量的小尺度磁性元素的出现。它们又相互作用，合并，形成成熟的太阳黑子。然而，由于观测设备的限制，亚弧秒分辨率的光球精细磁结构观测非常罕见。在这项工作中，利用1.6米古德太阳望远镜的高分辨率，我们共同分析了2017年7月13日NOAA AR 12665的矢量磁场，连续图像和Hα观测，目的是了解小尺度通量出现的特征，以及它们在光球和色球层中出现时的大气响应。在0.″1-0.″2的高分辨率下，我们的结果证实了两种小尺度磁通量涌现：与新形成的颗粒相关联的磁通量片涌现和传统的磁通量环涌现。在宽带TiO直接成像，我们观察到，这两种类型的磁通出现与变暗的颗粒边界，而只有磁通片拉长颗粒沿着新兴磁场的方向和横向扩展。在10 - 15分钟的寿命内，两种类型的出现的总垂直通量约为1018 Mx。垂直场和水平场的大小在通量片中是相当的，而在通量环中前者更强。Hα观测揭示了在磁环出现的事件中，机翼中的瞬时增亮，这很可能是埃勒曼炸弹的特征。
Recent observations demonstrated that emerging flux regions, which constitute the early stage of solar active regions, consist of emergence of numerous small-scale magnetic elements. They in turn interact, merge, and form mature sunspots. However, observations of fine magnetic structures on photosphere with subarcsecond resolution are very rare due to limitations of observing facilities. In this work, taking advantage of the high resolution of the 1.6 m Goode Solar Telescope, we jointly analyze vector magnetic fields, continuum images, and Hα observations of NOAA AR 12665 on 2017 July 13, with the goal of understanding the signatures of small-scale flux emergence, as well as their atmospheric responses as they emerge through multiple heights in the photosphere and chromosphere. Under such a high resolution of 0.″1–0.″2, our results confirm two kinds of small-scale flux emergence: magnetic flux sheet emergence associated with the newly forming granules, and the traditional magnetic flux loop emergence. With direct imaging in the broadband TiO, we observe that both types of flux emergence are associated with darkening of granular boundaries, while only flux sheets elongate granules along the direction of emerging magnetic fields and expand laterally. With a life span of 10 ∼ 15 minutes, the total emerged vertical flux is on the order of 1018 Mx for both types of emergence. The magnitudes of the vertical and horizontal fields are comparable in the flux sheets, while the former is stronger in flux loops. Hα observations reveal transient brightenings in the wings in the events of magnetic loop emergence, which are most probably the signatures of Ellerman bombs.