Small-Scale Activity Above the Penumbra of a Fast-Rotating Sunspot
Small-Scale Activity Above the Penumbra of a Fast-Rotating Sunspot
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DOI：
10.1007/s11207-018-1265-x
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发表时间：
2018-02
期刊：
影响因子：
2.8
通讯作者：
L. Bharti;C. Quintero Noda;S. Rakesh;B. Sobha;A. Pandya;C. Joshi
中科院分区：
文献类型：
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作者：
L. Bharti;C. Quintero Noda;S. Rakesh;B. Sobha;A. Pandya;C. Joshi
本文介绍了NOAA活动区10930快速旋转太阳黑子的丝状结构上的小尺度活动的高分辨率观测结果。进入本影的半影细丝显示出一个中心的暗核和亚结构。它几乎接近了本影的另一端，就像一座光桥。色球CaiiH图像显示了许多喷流状结构，其上方有一个明亮的前缘。这些明亮的喷流穿过灯丝尖端，呈现出协调的上下运动。过渡区域图像也显示在入侵上方的相同位置变亮。日冕195 Å图像显示，明亮的日冕环足点的一端位于这个结构中。入侵相对于本影具有相反的极性。沿侵入体长度的边缘处观察到强烈的下流，那里的反极性场增强。我们还观察到丝状结构中的反埃弗舍流，该流也显示了上层大气中的增亮和能量耗散。这种情况表明，喷流和变亮是由低空重联引起的，这种重联是由极性相反的磁场和这种结构上方的对流下流驱动的。
High-resolution observations of small-scale activity above the filamentary structure of a fast-rotating sunspot of NOAA Active Region 10930 are presented. The penumbral filament that intrudes into the umbra shows a central dark core and substructures. It almost approached another end of the umbra, like a light bridge. The chromospheric CaiiH images show many jet-like structures with a bright leading edge above it. These bright jets move across the filament tips and show coordinated up and down motions. Transition region images also show brightening at the same location above the intrusion. Coronal 195 Å images suggest that one end of the bright coronal loop footpoints resides in this structure. The intrusion has opposite polarity with respect to the umbra. Strong downflows are observed at the edges along the length of the intrusion where the opposite-polarity field is enhanced. We also observe a counter-Evershed flow in the filamentary structure that also displays brightening and energy dissipation in the upper atmosphere. This scenario suggests that the jets and brightenings are caused by low-altitude reconnection driven by opposite-polarity fields and convective downflows above such structures.