论文标题
活性区域中的冠状丰度：进化和基础色层和过渡区域特性
Coronal Abundances in an Active Region: Evolution and Underlying Chromospheric and Transition Region Properties
论文作者
论文摘要
太阳电晕和太阳风中的元素丰度通常与太阳光球的元素丰度不同，通常具有低初电离势的元素（FIP效应）。在这里，我们使用Hinode/eis光谱研究了大约10天的活性区域（AR）冠状化学成分的空间分布和时间演变，我们还分析了较低大气中FIP效应的任何证据，以研究色球和过渡区域的协调虹膜观察结果。为了得出冠状丰度，我们使用了最近为缪斯调查开发的光谱反演方法（Cheung etal。2019，de Pontieu等，2020）。我们发现，在研究的活动区域（AR 12738）中，冠状FIP偏置呈现显着的空间变化，其最高值（〜2.5-3.5）在AR边界的流出区域中，但通常适度的时间变异性。相对于AR核心，一些苔藓区域和AR黑子周围的某些区域显示出增强的FIP（〜2-2.5），AR核心的FIP偏置仅为〜1.5。在其中一些苔藓区域中，FIP偏置似乎最大。虹膜观察结果表明，在Mg II光谱的IRIS2反转中得出的色圈湍流在以高FIP偏置为特征的流出区域增强了，这为两种模型提供了重大的新约束，旨在解释AR溢出和化学分离模型的形成。
The element abundances in the solar corona and solar wind are often different from those of the solar photosphere, typically with a relative enrichment of elements with low first ionization potential (FIP effect). Here we study the spatial distribution and temporal evolution of the coronal chemical composition in an active region (AR) over about 10 days, using Hinode/EIS spectra, and we also analyze coordinated IRIS observations of the chromospheric and transition region emission to investigate any evidence of the footprints of the FIP effect in the lower atmosphere. To derive the coronal abundances we use a spectral inversion method recently developed for the MUSE investigation (Cheung et al. 2019, De Pontieu et al. 2020). We find that in the studied active region (AR 12738) the coronal FIP bias presents significant spatial variations, with its highest values (~ 2.5-3.5) in the outflow regions at the boundary of the AR, but typically modest temporal variability. Some moss regions and some regions around the AR sunspot show enhanced FIP (~ 2-2.5) with respect to the AR core, which has only a small FIP bias of ~1.5. The FIP bias appears most variable in some of these moss regions. The IRIS observations reveal that the chromospheric turbulence, as derived from IRIS2 inversions of the Mg II spectra, is enhanced in the outflow regions characterized by the high FIP bias, providing significant new constraints to both models aimed at explaining the formation of AR outflows and models of chemical fractionation.
