Correlated Spatio-temporal Evolution of Extreme-Ultraviolet Ribbons and Hard X-Rays in a Solar Flare
Correlated Spatio-temporal Evolution of Extreme-Ultraviolet Ribbons and Hard X-Rays in a Solar Flare
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DOI：
10.3847/1538-4357/ac4028
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发表时间：
2021-09
期刊：
影响因子：
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通讯作者：
S. Naus;J. Qiu;C. DeVore;S. Antiochos;J. Dahlin;J. Drake;M. Swisdak
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文献类型：
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作者：
S. Naus;J. Qiu;C. DeVore;S. Antiochos;J. Dahlin;J. Drake;M. Swisdak
我们使用来自界面区成像光谱仪和太阳动力学天文台（SDO）/大气成像组件（AIA）的紫外图像，来自SDO/日震和磁成像仪的磁数据，来自Ramaty高能太阳光谱成像仪的硬X射线（HXR）图像，和光变曲线从费米/伽玛射线暴监测器，以推断日冕磁场重联的性质。随着事件的发展，两个耀斑带远离磁极反转线。沿着带状延伸的新增亮锋的宽度在空间和时间上都是高度间歇性的，这大概反映了耀斑电流片结构和/或动力学的不均匀性。此外，带状宽度增长最迅速的区域表现出集中的非热HXR发射，与急剧增加略有HXR爆发之前。紫外发射的光曲线在光子能量高于25 keV时与HXR光曲线相匹配。在其他地区的带状宽度的演变和光变曲线不与HXR发射时间相关。这表明耀斑电流片内非热电子的产生是高度不均匀的。我们的研究结果表明，非热电子的产生和耀斑带状锋的局部增强的垂直范围之间有很强的联系，这反过来又反映了电流片的不均匀结构和/或重联动力学。尽管存在这种变化，但带状锋面仍然保持着几乎连续的准一维特征。因此，尽管重新连接的日冕电流片是高度结构化的，但它们仍然是准二维的，并且通过重新连接的磁通量系统地而不是随机地发生磁能释放。
We analyze the structure and evolution of ribbons from the M7.3 SOL2014-04-18T13 flare using ultraviolet images from the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA), magnetic data from the SDO/Helioseismic and Magnetic Imager, hard X-ray (HXR) images from the Reuven Ramaty High Energy Solar Spectroscopic Imager, and light curves from the Fermi/Gamma-ray Burst Monitor, in order to infer properties of coronal magnetic reconnection. As the event progresses, two flare ribbons spread away from the magnetic polarity inversion line. The width of the newly brightened front along the extension of the ribbon is highly intermittent in both space and time, presumably reflecting nonuniformities in the structure and/or dynamics of the flare current sheet. Furthermore, the ribbon width grows most rapidly in regions exhibiting concentrated nonthermal HXR emission, with sharp increases slightly preceding the HXR bursts. The light curve of the ultraviolet emission matches the HXR light curve at photon energies above 25 keV. In other regions the ribbon-width evolution and light curves do not temporally correlate with the HXR emission. This indicates that the production of nonthermal electrons is highly nonuniform within the flare current sheet. Our results suggest a strong connection between the production of nonthermal electrons and the locally enhanced perpendicular extent of flare ribbon fronts, which in turn reflects the inhomogeneous structure and/or reconnection dynamics of the current sheet. Despite this variability, the ribbon fronts remain nearly continuous, quasi-one-dimensional features. Thus, although the reconnecting coronal current sheets are highly structured, they remain quasi-two-dimensional and the magnetic energy release occurs systematically, rather than stochastically, through the volume of the reconnecting magnetic flux.