论文标题
冠状元素丰度：太阳X射线光谱的新结果
Coronal Elemental Abundance: New Results from Soft X-ray Spectroscopy of the Sun
论文作者
论文摘要
已知太阳电晕中的元素丰度与在太阳光球中观察到的元素不同。冠状动脉与光球丰度的比率表明了元素的第一个电离电位（FIP）的依赖性。我们使用涵盖一系列太阳能活动水平的多个空间任务的数据来估算从软X射线光谱中直接测量元素丰度的FIP偏差。这项全面的分析表明，在X射线耀斑的最大强度下，FIP偏置降低的明确证据，冠状丰度短暂趋向于光谱值，并且随着耀斑的衰减而缓慢恢复。对于低FIP元件Ca，Fe和Si的冠状丰度比具有中间值的S大。分馏程度的这些变化可能会提供输入，以在耀斑期间通过色球模型传播模型。
Elemental abundances in the solar corona are known to be different from those observed in the solar photosphere. The ratio of coronal to photospheric abundance shows a dependence on the first ionisation potential (FIP) of the element. We estimate FIP bias from direct measurements of elemental abundances from soft X-ray spectra using data from multiple space missions covering a range of solar activity levels. This comprehensive analysis shows clear evidence for a decrease in FIP bias around maximum intensity of the X-ray flare with coronal abundances briefly tending to photospheric values and a slow recovery as the flare decays. The departure from coronal abundances are larger for the low FIP elements Ca, Fe and Si than for S which have a mid FIP value. These changes in the degree of fractionation might provide inputs to model wave propagation through the chromosphere during flares.
