He i Vector Magnetic Field Maps of a Sunspot and Its Superpenumbral Fine-Structure
He i Vector Magnetic Field Maps of a Sunspot and Its Superpenumbral Fine-Structure
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太阳黑子的 He i 矢量磁场图及其超半影精细结构
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发表时间：
2015
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通讯作者：
A. Tritschler
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作者：
T. Schad;M. Penn;Haosheng Lin;A. Tritschler
对 1083 nm 处 He i 三重态的高分辨率光谱偏振观测进行高级反演，用于生成跨太阳黑子及其超半影冠层的色球磁场矢量的独特地图。这些观测结果是由邓恩太阳望远镜 (DST) 的设施红外分光偏振仪 (FIRS) 于 2012 年 1 月 29 日获得的。反演中采用了多种大气模型，因为超半影斯托克斯剖面以原子级偏振为主，而太阳黑子剖面则以塞曼为主，但也表现出可能由入射到色球材料上的辐射场的对称破缺效应引起的特征。我们推导了色球层中太阳黑子的平衡磁结构，并进一步表明，与观察到的强度结构不同，超半影磁场似乎没有精细结构。这表明原纤维不是磁通量的集中体，而是通过个体热化来区分。我们还直接将反演值与色球场的无电流外推进行比较。随着未来测量的改进，推断的磁场和势场之间的平均剪切角可能提供一种量化色球磁场的非势能的方法，以研究爆炸性太阳现象的发生。
Advanced inversions of high-resolution spectropolarimetric observations of the He i triplet at 1083 nm are used to generate unique maps of the chromospheric magnetic field vector across a sunspot and its superpenumbral canopy. The observations were acquired by the Facility Infrared Spectropolarimeter (FIRS) at the Dunn Solar Telescope (DST) on 29 January 2012. Multiple atmospheric models are employed in the inversions because superpenumbral Stokes profiles are dominated by atomic-level polarization, while sunspot profiles are Zeeman-dominated, but also exhibit signatures that might be induced by symmetry-breaking effects of the radiation field incident on the chromospheric material. We derive the equilibrium magnetic structure of a sunspot in the chromosphere and furthermore show that the superpenumbral magnetic field does not appear to be finely structured, unlike the observed intensity structure. This suggests that fibrils are not concentrations of magnetic flux, but are instead distinguished by individualized thermalization. We also directly compare our inverted values with a current-free extrapolation of the chromospheric field. With improved measurements in the future, the average shear angle between the inferred magnetic field and the potential field may offer a means to quantify the non-potentiality of the chromospheric magnetic field to study the onset of explosive solar phenomena.