Statistical Study of Chromospheric Evaporation in Impulsive Phase of Solar Flares
Statistical Study of Chromospheric Evaporation in Impulsive Phase of Solar Flares
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DOI：
10.3847/1538-4357/aaf6b0
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发表时间：
2018-05
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影响因子：
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通讯作者：
V. Sadykov;A. Kosovichev;I. Sharykin;G. Kerr
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文献类型：
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作者：
V. Sadykov;A. Kosovichev;I. Sharykin;G. Kerr
我们提出了一个统计研究色球蒸发太阳耀斑使用的RHESSI X射线望远镜和界面区域成像光谱仪紫外光谱仪同时观测。结果与F-CHROMA RADYN数据库中的辐射流体动力学耀斑模型进行了比较。对于每一个事件，我们研究了空间分辨多普勒频移的光谱线形成的过渡区（C二1334.5 <$）和热日冕等离子体（Fe XXI 1354.1 <$），调查太阳大气的动力学在耀斑脉冲阶段。我们估计的能量通量沉积的高能电子使用X射线成像光谱学，并假设标准的厚靶模型。利用RADYN耀斑模型、RH1.5D辐射传输程序和Chianti原子线数据库，计算了Cii和Fexxi的谱线轮廓，并与观测结果进行了比较。虽然RADYN模型预测的多普勒频移和沉积的能量通量的两条线之间的相关性，这是只观察到的C二数据。几个定量的观测和模型之间的差异被发现：Fe XXI多普勒频移的模型比在数据中，和C二平均蓝移是不存在的观测，但预测的模型。根据观测值估算的“温和”和“爆发”蒸发状态之间的转换能量（erg cm−2 s−1）和根据模型推导的转换能量（erg cm−2 s−1）彼此相当。结果表明色球蒸发的过程之间的关系，冷层的响应，和耀斑能量通量沉积的高能电子，虽然表现出分析的观测和RADYN模型之间的差异。
We present a statistical study of chromospheric evaporation in solar flares using simultaneous observations by the RHESSI X-ray telescope and the Interface Region Imaging Spectrograph UV spectrograph. The results are compared with radiation hydrodynamic flare models from the F-CHROMA RADYN database. For each event, we study spatially resolved Doppler shifts of spectral lines formed in the transition region (C ii 1334.5 Å) and hot coronal plasma (Fe xxi 1354.1 Å) to investigate the dynamics of the solar atmosphere during the flare impulsive phase. We estimate the energy fluxes deposited by high-energy electrons using X-ray imaging spectroscopy and assuming the standard thick-target model. Using the RADYN flare models, the RH 1.5D radiative transfer code, and the Chianti atomic line database, we calculate C ii and Fe xxi line profiles and compare with the observations. While the RADYN models predict a correlation between the Doppler shifts and deposited energy flux for both lines, this was only observed in the C ii data. Several quantitative discrepancies are found between the observations and models: the Fe xxi Doppler shifts are substantially stronger in the models than in the data, and the C ii mean blueshifts are absent in the observations but predicted by the models. The transition energies between “gentle” and “explosive” evaporation regimes estimated from the observations ( erg cm−2 s−1) and derived from the models ( erg cm−2 s−1) are comparable with each other. The results illustrate relationships among the processes of chromospheric evaporation, the response of the colder layers, and the flare energy flux deposited by high-energy electrons, although demonstrating discrepancy between analyzed observations and RADYN models.