Signatures of Magnetic Reconnection at the Footpoints of Fan-shaped Jets on a Light Bridge Driven by Photospheric Convective Motions
Signatures of Magnetic Reconnection at the Footpoints of Fan-shaped Jets on a Light Bridge Driven by Photospheric Convective Motions
复制标题
光球对流运动驱动的光桥上扇形喷流足点的磁重联特征
DOI：
10.3847/1538-4357/aaf1d1
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发表时间：
2019
影响因子：
4.9
通讯作者：
Ji Kaifan
中科院分区：
文献类型：
--
作者：
Bai Xianyong;Socas-Navarro Hector;Nobrega-Siverio Daniel;Su Jiangtao;Deng Yuanyong;Li Dong;Cao Wenda;Ji Kaifan
动态喷流通常出现在光桥（LB）上，这是研究太阳黑子衰变的关键。到目前为止，它们的形成机制还不完全清楚。在本文中，我们使用了最先进的观测从古德太阳望远镜，界面区域成像光谱仪，光谱偏振仪在板日出，和大气成像组件（AIA）在船上的太阳动力学天文台详细分析的扇形喷流的LB。从Hα速度可以看出，喷流在上升阶段有一个持续12分钟的上升运动，这与Hα线翼的增强有关。在AIA 171和AIA 193通道中可见的扇形喷流的明亮前部出现两个迷你喷流，时间间隔短至1分钟。光球图像中识别出两种小尺度对流运动，沿着Hα线翼增强。一个似乎与新对流单体的形成有关，另一个表现为穿过对流单体的暗巷的运动。三波瓣Stokes V剖面的发现及其NICOLE反演结果表明，LB中存在极性相反的磁力线。从Hα-0.8的图像中，我们发现带状增亮沿着LB传播，可能表明滑移重联。我们的观测结果支持这一观点，即所研究的扇形喷流是由磁场重联引起的，光球对流运动在触发磁场重联中起着重要作用。
Dynamical jets are generally found on light bridges (LBs), which are key to studying sunspot decay. So far, their formation mechanism is not fully understood. In this paper, we used state-of-the-art observations from the Goode Solar Telescope, the Interface Region Imaging Spectrograph, the Spectro-polarimeter on board Hinode, and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory to analyze the fan-shaped jets on LBs in detail. A continuous upward motion of the jets in the ascending phase is found from the Hα velocity that lasts for 12 minutes and is associated with the Hα line wing enhancements. Two mini jets appear on the bright fronts of the fan-shaped jets visible in the AIA 171 and 193 Å channels, with a time interval as short as 1 minute. Two kinds of small-scale convective motions are identified in the photospheric images, along with the Hα line wing enhancements. One seems to be associated with the formation of a new convection cell, and the other manifests as the motion of a dark lane passing through the convection cell. The finding of three-lobe Stokes V profiles and their inversion with the NICOLE code indicate that there are magnetic field lines with opposite polarities in LBs. From the Hα −0.8 Å images, we found ribbon-like brightenings propagating along the LBs, possibly indicating slipping reconnection. Our observation supports the idea that the fan-shaped jets under study are caused by magnetic reconnection, and photospheric convective motions play an important role in triggering the magnetic reconnection.