Dynamics of the solar active region finestructure
Dynamics of the solar active region finestructure
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DOI：
10.1051/0004-6361:20031305
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发表时间：
2003-12
影响因子：
6.5
通讯作者：
B. Bovelet;E. Wiehr
中科院分区：
文献类型：
--
作者：
B. Bovelet;E. Wiehr
我们调查的精细结构的动力学行为，在太阳黑子的周围环境和半影从斑点重建的60分钟的时间序列采取的45厘米荷兰开放望远镜（DOT）在La Palma。在1 nm的光谱窗口包含的G-波段，我们确定每个功能的面积和它的时间演变的模式识别，特别是适合于分离明亮的颗粒边缘从颗粒间G-波段亮点（BP）。每一个BP的演变显示出比强度更强的面积变化。我们分析了BP的水平运动作为其距离太阳黑子中心的函数。在一个6毫米的环外太阳黑子边界，大多数BP（4/5）径向向外移动，他们比少数（1/5）向内移动的BP更快。这两个速度的差异表明了一个径向向外的漂移，从外半影边缘的大约0.3 km s −1减少到距离黑子中心大约20 Mm（28 °）处的零;我们将这个空间范围解释为黑子“护城河”的延伸。这一发现支持了太阳地震层析成像测量和理论预测的深层巨大滚动的想法。在半影内部，我们发现4/5的半影亮结构（PBS）向内移动，平均速度为0.8 km s-1。1/5的向外移动PBS几乎完全位于外半影;它们的平均速度为0.8 km s-1，与半影MHD模型一致，同样发现外半影中的半影暗结构（PDS）。
We investigate the dynamical behavior of the finestructure in a sunspot's surroundings and its penumbra from a speckle-reconstructed 60 min time series taken at the 45 cm Dutch Open Telescope (DOT) on La Palma. In the 1 nm spectral window containing the G-band, we determine the area of each feature and its time evolution by means of pattern recognition, particularly adapted to separate bright granular edges from inter-granular G-band bright points (BP). The evolution of each individual BP shows a stronger variation of the area than of the intensity. We analyze the horizontal motions of BP as a function of their distance from the sunspot center. Within a 6 Mm ring around the outer sunspot border, most BP (4/5) move radially outwards; they are faster than the minority (1/5) of inward moving BP. The difference of both velocities indicates a radial outward drift which decreases from about 0.3 km s −1 at the outer penumbral border to zero at about 20 Mm distance (28 �� ) from the sunspot center; a spatial range that we interpret as the extension of the sunpot "moat". This finding supports the idea of giant rolls in deep layers measured by helio-seismic tomography and predicted by theory. Inside the penumbra, we find a 4/5 majority of penumbral bright structures (PBS) to move inwards with a mean velocity of 0.8 km s −1 .T he 1/5 minority of outward moving PBS is almost entirely located in the outer penumbra; their mean velocity of 0.8 km s −1 is equally found for penumbral dark structures (PDS) in the outer penumbra, in agreement with penumbral MHD models.