CHARACTERISTIC DEPENDENCE OF UMBRAL DOTS ON THEIR MAGNETIC STRUCTURE
CHARACTERISTIC DEPENDENCE OF UMBRAL DOTS ON THEIR MAGNETIC STRUCTURE
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DOI：
10.1088/0004-637x/702/2/1048
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发表时间：
2009-07
期刊：
影响因子：
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通讯作者：
H. Watanabe;R. Kitai;K. Ichimoto
中科院分区：
文献类型：
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作者：
H. Watanabe;R. Kitai;K. Ichimoto
2007年3月1日，日野太阳光学望远镜在NOAA 10944的一个稳定的太阳黑子上观测到本影点。观测程序包括蓝色连续光谱图像和Fe 630nm谱线的光谱偏振谱图。将UDs自动检测算法应用于连续2小时的蓝色连续体图像，并根据获取的数据计算UDs的寿命、大小和固有运动。太阳黑子的磁结构是通过光谱偏振剖面的反演得到的。我们计算了UD的参数（大小、寿命、发生率、固有运动）与磁场（场强、倾角、方位角）的相关性，得到如下结果：(1)无论出射点的磁场强度如何，UDs的寿命和尺寸几乎是恒定的。(2)随出爆点场倾角的增大，爆点速度增大。(3)在强倾斜磁场区域，磁阱的运动方向与磁场水平分量的方向基本平行，而在弱倾斜磁场区域，磁阱几乎没有固有运动。我们的结果描述了太阳黑子中磁对流的基本性质。我们将讨论我们的结果与最近由sch<s:1> ssler & Vögler和Rempel等人进行的磁流体动力学模拟进行比较。
Umbral dots (UDs) were observed in a stable sunspot in NOAA 10944 by the Hinode Solar Optical Telescope on 2007 March 1. The observation program consisted of blue continuum images and spectropolarimetric profiles of Fe i 630 nm line. An automatic detection algorithm for UDs was applied to the 2 hr continuous blue continuum images, and using the obtained data, the lifetime, size, and proper motion of UDs were calculated. The magnetic structure of the sunspot was derived through the inversion of the spectropolarimetric profiles. We calculated the correlations between UD's parameters (size, lifetime, occurrence rate, proper motion) and magnetic fields (field strength, inclination, azimuth), and obtained the following results. (1) Both the lifetime and size of UDs are almost constant regardless of the magnetic field strength at their emergence site. (2) The speed of UDs increases as the field inclination angle at their emergence site gets larger. (3) The direction of movement of UDs is nearly parallel to the direction of the horizontal component of magnetic field in the region with strongly inclined field, while UDs in the region with weakly inclined field show virtually no proper motion. Our results describe the basic properties of magnetoconvection in sunspots. We will discuss our results in comparison to recent magnetohydrodynamic simulations by Schüssler & Vögler and Rempel et al.