COOL TRANSITION REGION LOOPS OBSERVED BY THE INTERFACE REGION IMAGING SPECTROGRAPH
COOL TRANSITION REGION LOOPS OBSERVED BY THE INTERFACE REGION IMAGING SPECTROGRAPH
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DOI：
10.1088/0004-637x/810/1/46
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发表时间：
2015-07
期刊：
影响因子：
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通讯作者：
Zhenghua Huang;L. Xia;Bo Li;M. Madjarska
中科院分区：
文献类型：
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作者：
Zhenghua Huang;L. Xia;Bo Li;M. Madjarska
我们报告的第一个接口区域成像光谱仪（IRIS）研究冷过渡区环路，一类环路，在文献中很少受到关注。在活动区NOAA 11934的太阳盘面上，在Si iv 1402.8 μ m光谱光栅和1400 μ m裂隙-颚图像中观察到了一组这样的环。我们把这些回路分成三组，并研究它们的动力学。第一组包括相对稳定的环路，横截面为382-626公里。观测到的多普勒速度暗示着虹吸流，从环的一端的−10 km s−1逐渐变化到另一端的20 km s−1。测得的非热速度为15 ~ 25 km s−1。在蓝移的足点处发现了速率为1015 Mx s−1的磁抵消。这些物理性质表明，这些环是由磁重联脉冲加热的，虹吸流在能量重新分配中起着重要作用。第二组对应于两个立足于混合磁极区域的足点，在那里观测到了速率为1015 Mx s−1的磁抵消和具有高达200 km s−1的增强翼的爆炸事件线轮廓。在第三组中，观察到两个冷却回路系统之间的相互作用。两个环系统之间的磁重联的证据反映在爆炸事件线轮廓和磁抵消率为3 × 10 15？> Mx s−1在相应区域观察到。IRIS为深入研究冷过渡区环流提供了机会。进一步的数值实验对于了解它们的物理特性及其在日冕加热过程中的作用至关重要。
We report on the first Interface Region Imaging Spectrograph (IRIS) study of cool transition region loops, a class of loops that has received little attention in the literature. A cluster of such loops was observed on the solar disk in active region NOAA11934, in the Si iv 1402.8 Å spectral raster and 1400 Å slit-jaw images. We divide the loops into three groups and study their dynamics. The first group comprises relatively stable loops, with 382–626 km cross-sections. Observed Doppler velocities are suggestive of siphon flows, gradually changing from −10 km s−1 at one end to 20 km s−1 at the other end of the loops. Nonthermal velocities of 15 ∼ 25 km s−1 were determined. Magnetic cancellation with a rate of 1015 Mx s−1 is found at the blueshifted footpoints. These physical properties suggest that these loops are impulsively heated by magnetic reconnection, and the siphon flows play an important role in the energy redistribution. The second group corresponds to two footpoints rooted in mixed-magnetic-polarity regions, where magnetic cancellation with a rate of 1015 Mx s−1 and explosive-event line profiles with enhanced wings of up to 200 km s−1 were observed. In the third group, interaction between two cool loop systems is observed. Evidence for magnetic reconnection between the two loop systems is reflected in the explosive-event line profiles and magnetic cancellation with a rate of 3 × 10 15 ?> Mx s−1 observed in the corresponding area. The IRIS has provided opportunity for in-depth investigations of cool transition region loops. Further numerical experiments are crucial for understanding their physics and their roles in the coronal heating processes.