Brown Gerrard M, Labrosse Nicolas
SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ UK.
Sol Phys. 2018;293(2):35. doi: 10.1007/s11207-018-1255-z. Epub 2018 Feb 9.
Coronal structures receive radiation not only from the solar disc, but also from the corona. This height-dependent incident radiation plays a crucial role in the excitation and the ionisation of the illuminated plasma. The aim of this article is to present a method for computing the detailed incident radiation coming from the solar corona, which is perceived at a point located at an arbitrary height. The coronal radiation is calculated by integrating the radiation received at a point in the corona over all of the corona visible from this point. The emission from the corona at all wavelengths of interest is computed using atomic data provided by CHIANTI. We obtain the spectrum illuminating points located at varying heights in the corona at wavelengths between 100 and 912 Å when photons can ionise H or He atoms and ions in their ground states. As expected, individual spectral lines will contribute most at the height within the corona where the local temperature is closest to their formation temperature. As there are many spectral lines produced by many ions, the coronal intensity cannot be assumed to vary in the same way at all wavelengths and so must be calculated for each separate height that is to be considered. This code can be used to compute the spectrum from the corona illuminating a point at any given height above the solar surface. This brings a necessary improvement to models where an accurate determination of the excitation and ionisation states of coronal plasma structures is crucial.
日冕结构不仅接收来自太阳盘面的辐射，还接收来自日冕本身的辐射。这种与高度相关的入射辐射在被照亮等离子体的激发和电离过程中起着至关重要的作用。本文的目的是提出一种计算来自日冕的详细入射辐射的方法，该辐射在位于任意高度的一点上被感知。日冕辐射是通过对从该点可见的整个日冕中某一点接收到的辐射进行积分来计算的。使用CHIANTI提供的原子数据计算日冕在所有感兴趣波长处的发射。当光子能够电离处于基态的H或He原子及离子时，我们得到了日冕中位于不同高度的点在100至912埃波长范围内的光谱。正如预期的那样，各个光谱线在日冕中局部温度最接近其形成温度的高度处贡献最大。由于许多离子会产生许多光谱线，不能假定日冕强度在所有波长下都以相同方式变化，因此必须针对每个要考虑的单独高度进行计算。此代码可用于计算来自日冕的光谱，该光谱照亮太阳表面上方任意给定高度处的一点。这为那些精确确定日冕等离子体结构的激发和电离状态至关重要的模型带来了必要的改进。
