A Solar Magnetic-fan Flaring Arch Heated by Nonthermal Particles and Hot Plasma from an X-Ray Jet Eruption
A Solar Magnetic-fan Flaring Arch Heated by Nonthermal Particles and Hot Plasma from an X-Ray Jet Eruption
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DOI：
10.3847/1538-4357/ab8bce
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发表时间：
2020-05
期刊：
影响因子：
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通讯作者：
Kyoung-Sun Lee;H. Hara;Kyoko Watanabe;A. Joshi;D. Brooks;S. Imada;A. Prasad;Phillip Dang;
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文献类型：
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作者：
Kyoung-Sun Lee;H. Hara;Kyoko Watanabe;A. Joshi;D. Brooks;S. Imada;A. Prasad;Phillip Dang;
我们研究了一次M1.3肢体耀斑，它形成了一个磁环/拱形，从X射线喷流中呈扇形展开。利用Hinode/EIS，我们发现耀斑期间环顶温度随着高度的增加而升高，达到107K以上。观测到的多普勒速度(S−1红移10 0~5 0 0公里)和来自Fexxiv的非热速度(≥10 0 km S−1)也随环高的增加而增大。电子密度从耀斑上升初期的0.3×10 9 cm−3增加到耀斑出现后的1.3×10 9 cm−3。由日地关系天文台/EUV成像仪得到的环圈的3D结构表明，环顶区域的强烈红移是由于喷流产生的等离子体上行所致。鲁文·拉马蒂高能太阳光谱成像仪的硬X射线和软X射线发射在耀斑的脉冲阶段仅被视为脚点增亮，然后软X射线发射在衰变阶段移动到环顶。根据温度、密度测量和理论冷却模型，火炬拱的温度演变符合喷流喷发期间的脉冲加热，随后是蒸发传导冷却和风机环顶的少量持续加热。通过对太阳动力学天文台/HMI的磁场拓扑和挤压因子图的研究，我们得出结论：观测到的磁扇耀斑拱形的热量主要来自伴随喷流喷出的低层大气重联，而不是标准耀斑模型中所预期的来自拱形上方的重联。
We have investigated an M1.3 limb flare, which develops as a magnetic loop/arch that fans out from an X-ray jet. Using Hinode/EIS, we found that the temperature increases with height to a value of over 107 K at the loop top during the flare. The measured Doppler velocity (redshifts of 100–500 km s−1) and the nonthermal velocity (≥100 km s−1) from Fe xxiv also increase with loop height. The electron density increases from 0.3 × 109 cm−3 early in the flare rise to 1.3 × 109 cm−3 after the flare peak. The 3D structure of the loop derived with Solar TErrestrial RElations Observatory/EUV Imager indicates that the strong redshift in the loop-top region is due to upflowing plasma originating from the jet. Both hard X-ray and soft X-ray emission from the Reuven Ramaty High Energy Solar Spectroscopic Imager were only seen as footpoint brightenings during the impulsive phase of the flare, then, soft X-ray emission moved to the loop top in the decay phase. Based on the temperature and density measurements and theoretical cooling models, the temperature evolution of the flare arch is consistent with impulsive heating during the jet eruption followed by conductive cooling via evaporation and minor prolonged heating in the top of the fan loop. Investigating the magnetic field topology and squashing factor map from Solar Dynamics Observatory/HMI, we conclude that the observed magnetic-fan flaring arch is mostly heated from low atmospheric reconnection accompanying the jet ejection, instead of from reconnection above the arch as expected in the standard flare model.