Collapsed, uncollapsed, and hidden magnetic flux on the quiet Sun
Collapsed, uncollapsed, and hidden magnetic flux on the quiet Sun
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安静的太阳上坍缩、未坍缩和隐藏的磁通量
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发表时间：
2011
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通讯作者：
J. Stenflo
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作者：
J. Stenflo
自从20世纪70年代初斯托克斯V线比和80年代初汉勒去极化效应的首次应用以来，我们对平静的太阳磁性有了一个二元的看法：间歇性的kG通量管被强度为10-100 G的湍流场的海洋所包围。有人担心，这种二元论可能是使用两种几乎相互排斥的诊断工具，塞曼和汉勒效应的假象。然而，我们发现，单独的日野线比数据，没有任何参考Hanle效应，揭示了两个不同的通量人口的存在，代表强（崩溃）和弱（未崩溃）通量。坍塌的人口优先位于颗粒间通道，而未坍塌的人口是最明显的明亮的细胞内部。从内禀场强（由坍缩粒子数的线比导出）和相应的通量密度之间的比较，我们可以推导出通量管的尺寸分布。其中大多数被发现具有10-70公里的范围内的大小。本征通量管场强度随着尺寸减小而减小，对于小于约60 km的尺寸，变得基本上小于kG。无符号通量密度的平均值之间的比较在日出宁静太阳数据集和早期的限制从汉勒去极化效应表明，大部分的磁通量保持不可见的日出分辨率尺度由于取消的空间分辨率元素内的相反的磁极性。我们已经推导出的抵消函数，描述了如何提高空间分辨率的隐藏通量的可见性。它需要外推到极小的尺度之前，由汉勒效应施加的约束得到满足，这表明，隐藏的磁通量的大部分驻留在磁标度谱（10 m级）的末端附近的尺度。
Since the first applications of the Stokes V line ratio in the early 1970s and the Hanle depolarization effect in the early 1980s we have had a dualistic view of quiet-Sun magnetism: intermittent kG flux tubes surrounded by an ocean of turbulent fields with strengths of order 10-100 G. There has been the concern that this dualism could be an artefact of using two mutually almost exclusive diagnostic tools, the Zeeman and Hanle effect. We find however that the Hinode line-ratio data alone, without any reference to the Hanle effect, reveal the existence of two distinct flux populations, representing strong (collapsed) and weak (uncollapsed) flux. The collapsed population is preferentially located in the intergranular lanes, while the uncollapsed population is most visible in the bright cell interiors. From a comparison between the intrinsic field strengths, as derived from the line ratio for the collapsed population, and the corresponding flux densities, we can deduce the size distribution of the flux tubes. The majority of them are found to have sizes in the range 10-70 km. The intrinsic flux tube field strength decreases with diminishing size to become substantially smaller than kG for sizes below about 60 km. Comparison between the average of the unsigned flux density in the Hinode quiet-Sun data set and earlier constraints from the Hanle depolarization effect shows that most of the flux remains invisible at the Hinode resolution scale due to cancellation of the opposite magnetic polarities within the spatial resolution element. We have derived the cancellation function that describes how the visibility of the hidden flux improves with increased spatial resolution. It needs to be extrapolated to extremely small scales before the constraints imposed by the Hanle effect get satified, which suggests that the bulk of the hidden flux resides at scales near the end of the magnetic scale spectrum (of order 10 m).