Flare-induced Photospheric Velocity Diagnostics
Flare-induced Photospheric Velocity Diagnostics
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DOI：
10.3847/1538-4357/abfda8
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
A. J. Monson;M. Mathioudakis;A. Reid;R. Milligan;D. Kuridze
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文献类型：
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作者：
A. J. Monson;M. Mathioudakis;A. Reid;R. Milligan;D. Kuridze
利用RADYN和RH程序对太阳耀斑进行了辐射流体动力学模拟，研究了电子束加热引起的光球Fe i谱线扰动。我们调查如何在光束参数的变化导致在诱导光球速度的可辨别的差异。谱线合成揭示了色球对谱线轮廓的显著贡献，导致在接近最大束流加热时间时，明显的红色不对称性高达40 m s−1，这并不能反映当时辐射流体动力学模拟所产生的上升流速度。整个谱线轮廓的表观红移是由显着的色球发射产生的，其蓝移高达400 m s−1，并填充了近稳态光球吸收轮廓的蓝色一侧。因此，在耀斑期间从光球线剖面中可以得到的速度信息必须小心处理，以减轻大气较高部分提供错误速度信号的影响。
We present radiative-hydrodynamic simulations of solar flares generated by the RADYN and RH codes to study the perturbations induced in photospheric Fe i lines by electron beam heating. We investigate how variations in the beam parameters result in discernible differences in the induced photospheric velocities. Line synthesis revealed a significant chromospheric contribution to the line profiles resulting in an apparent red asymmetry by as much as 40 m s−1 close to the time of maximum beam heating, which was not reflective of the upflow velocities that arose from the radiative-hydrodynamic simulations at those times. The apparent redshift to the overall line profile was produced by significant chromospheric emission that was blueshifted by as much as 400 m s−1 and fills in the blue side of the near-stationary photospheric absorption profile. The velocity information that can be retrieved from photospheric line profiles during flares must therefore be treated with care to mitigate the effects of higher parts of the atmosphere providing an erroneous velocity signal.