Various Local Heating Events in the Earliest Phase of Flux Emergence
Various Local Heating Events in the Earliest Phase of Flux Emergence
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DOI：
10.3847/1538-4357/836/1/63
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发表时间：
2017-01
期刊：
影响因子：
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通讯作者：
S. Toriumi;Y. Katsukawa;M. Cheung
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文献类型：
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作者：
S. Toriumi;Y. Katsukawa;M. Cheung
新兴通量区（EFR）是已知的表现出各种零星的局部加热事件在低层大气。为了研究这些事件的特征，特别是将光球磁场和大气动力学联系起来，我们分析了NOAA AR 12401中新EFR的Hinode，界面区域成像光谱仪（IRIS）和太阳动力学观测数据。在Hinode/SOT Ca图像中识别的151个亮点（BP）中，有29个被SOT/SP扫描重叠。在EFR中心的七个BPs具有混合极性的光球磁背景。它们的IRIS UV光谱（例如，Si iv 1402.8 <$）被强烈增强，并有红色或蓝色的变化，尾部延伸，这高度暗示了双向喷流;每次增亮持续10-15分钟，留下耀斑般的光变曲线。这组中的大多数都显示出秃斑，即U形光球磁环。另外10个BP位于EFR边缘的单极区。它们通常在紫外线强度较弱，并表现出系统的红移与多普勒速度高达，这可能超过当地的声速在过渡区。这两种类型的BP显示出强烈的温度上升的迹象，在低色球层。这些观测结果支持的物理图片，加热事件在EFR中心是由于磁重联内取消起伏的领域，如埃勒曼炸弹，而周边加热事件是由于冲击或强烈的压缩所造成的快速下降流沿着覆盖的拱形灯丝系统。
Emerging flux regions (EFRs) are known to exhibit various sporadic local heating events in the lower atmosphere. To investigate the characteristics of these events, especially to link the photospheric magnetic fields and atmospheric dynamics, we analyze Hinode, Interface Region Imaging Spectrograph (IRIS), and Solar Dynamics Observatory data of a new EFR in NOAA AR 12401. Out of 151 bright points (BPs) identified in Hinode/SOT Ca images, 29 are overlapped by an SOT/SP scan. Seven BPs in the EFR center possess mixed-polarity magnetic backgrounds in the photosphere. Their IRIS UV spectra (e.g., Si iv 1402.8 Å) are strongly enhanced and red- or blueshifted, with tails reaching , which is highly suggestive of bi-directional jets; each brightening lasts for 10–15 minutes, leaving flare-like light curves. Most of this group show bald patches, the U-shaped photospheric magnetic loops. Another 10 BPs are found in unipolar regions at the EFR edges. They are generally weaker in UV intensities and exhibit systematic redshifts with Doppler speeds up to , which could exceed the local sound speed in the transition region. Both types of BPs show signs of strong temperature increase in the low chromosphere. These observational results support the physical picture that heating events in the EFR center are due to magnetic reconnection within cancelling undular fields like Ellerman bombs, while the peripheral heating events are due to shocks or strong compressions caused by fast downflows along the overlying arch filament system.