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arXiv 2006.00574astro-ph.SR
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SDO/AIA观测的冷耀斑环氦连续谱特征

Signatures of Helium continuum in cool flare loops observed by SDO/AIA

Petr Heinzel, Pavol Schwartz, Juraj Lörinčík, Július Koza, Sonja Jejčič, David Kuridze

摘要:

我们对SDO/AIA在SOL 2017 -09- 10 T16:06 X8.2级耀斑的渐变阶段观察到的离翼冷耀斑环进行了分析。在从335 ° C开始的EUV通道中,冷环出现为与亮环拱廊相对的暗结构。这些黑暗的结构精确coaligned(空间和时间)与环观察SST在氢和离子钙的发射线。最近发表的基于SST观测的冷环半经验模型为我们预测氢氦复合连续谱的水平提供了依据。使用近似非LTE方法合成连续谱,然后将理论光谱转换为AIA信号。与暗环内检测到的信号的比较表明,只有在AIA 211通道中,计算出的复合连续谱水平与某些模型的观测结果一致,而在距离连续谱边缘更远的所有其他通道中,合成连续谱太低。在类比与磁盘上的观测耀斑,我们解释的盈余排放,由于大量的EUV线发射的热,但在前面的冷的暗淡的环路。最后,我们简要地评论了标准吸收模型在分析暗环亮度时的失败。

英文摘要:

We present an analysis of off-limb cool flare loops observed by SDO/AIA during the gradual phase of SOL2017-09-10T16:06 X8.2-class flare. In the EUV channels starting from the 335 Å one, cool loops appear as dark structures against the bright loop arcade. These dark structures were precisely coaligned (spatially and temporally) with loops observed by SST in emission lines of hydrogen and ionized calcium. Recently published semi-empirical model of cool loops based on SST observations serves us to predict the level of hydrogen and helium recombination continua. The continua were synthesized using an approximate non-LTE approach and theoretical spectra were then transformed to AIA signals. Comparison with signals detected inside the dark loops shows that only in AIA 211 Å channel the computed level of recombination continua is consistent with observations for some models, while in all other channels which are more distant from the continua edges the synthetic continuum is far too low. In analogy with on-disk observations of flares we interpret the surplus emission as due to numerous EUV lines emitted from hot but faint loops in front of the cool ones. Finally we briefly comment on failure of the standard absorption model when used for analysis of the dark-loop brightness.

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