Behaviour of molecular hydrogen emission in three solar flares
Behaviour of molecular hydrogen emission in three solar flares
复制标题
三个太阳耀斑中氢分子发射的行为
DOI：
10.1093/mnras/stad2853
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发表时间：
2023
影响因子：
4.8
通讯作者：
Mulay S
中科院分区：
文献类型：
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作者：
Mulay S
我们使用界面区域成像光谱仪 (IRIS) 系统地研究了 2014 年 10 月 25 日 C5.1、C9.7 和 X1.0 级的三个 X 射线耀斑期间氢分子 (H2) 的紫外线 (UV) 发射。耀斑带中出现了 5 条 H2 谱线的显着发射，解释为由于吸收了两条 Siiv 谱线的紫外线辐射而产生的光激发（荧光）。 H2 剖面很宽，除了固定成分外，还包含两个非固定成分（红色和蓝色翼）。红翼（蓝翼）分量显示出~5–15 km s−1（∼5–10 km s−1）的小红移（蓝移）。发现非热速度为 ∼5–15 km s−1。 H2 线强度与其分支比之间的相互关系证实，H2 发射是在光学稀等离子体条件下形成的。 Siivand H2 发射之间存在很强的空间和时间相关性，但 H2 发射更加广泛和分散，进一步表明 H2 荧光，并且通过与耀斑“回暖”类比，提供了一种估计 H2 发射起源深度的方法。我们发现，这位于 Siivemission 源头下方 1871 ± 157 公里和 1207 ± 112 公里处，位于两个不同的带状位置。
We have systematically investigated ultraviolet (UV) emission from molecular hydrogen (H2) using theInterface Region Imaging Spectrograph (IRIS), during three X-ray flares of C5.1, C9.7, and X1.0 classes on 2014 October 25. Significant emission from five H2spectral lines appeared in the flare ribbons, interpreted as photoexcitation (fluorescence) due to the absorption of UV radiation from two Siivspectral lines. The H2profiles were broad and consisted of two non-stationary components in red and in the blue wings of the line in addition to the stationary component. The red-wing (blue-wing) components showed small redshifts (blueshifts) of ∼5–15 km s−1(∼5–10 km s−1). The non-thermal velocities were found to be ∼5–15 km s−1. The interrelation between intensities of H2lines and their branching ratios confirmed that H2emission formed under optically thin plasma conditions. There is a strong spatial and temporal correlation between Siivand H2emissions, but the H2emission is more extended and diffuse, further suggesting H2fluorescence, and – by analogy with flare ‘back-warming’ – providing a means to estimate the depth from which the H2emission originates. We find that this is 1871 ± 157 and 1207 ± 112 km below the source of the Siivemission, in two different ribbon locations.