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arXiv 1205.6533astro-ph.SR
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用矢量磁场观测量化太阳超活动区

Quantifying solar superactive regions with vector magnetic field observations

A. Q. Chen, J. X. Wang

摘要:

超活动区(SAR)的矢量磁场特征是理解SAR异常活跃的关键,也是指导空间天气预报的重要依据。我们的目标是利用怀柔太阳观测站太阳磁场望远镜拍摄的矢量磁图来量化SAR的特性。利用4个参数分析了第22和23太阳活动周14个SAR的矢量磁场特征:1)相反极性间的磁通量不平衡,2)光球总自由磁能,3)具有陡峭水平磁梯度的磁中性线长度,4)强磁剪切区面积。此外,我们选择了另外八个大的和不活跃的活动区(AR),这被称为休闲AR(FAR),比较它们与SAR。我们发现大多数合成孔径雷达的净磁通量大于7.0 \times 10^21 Mx,光球总自由磁能大于1.0 \times 10^24 erg/cm,磁中性线具有陡峭的水平磁梯度(\geq 300 G/Mm)大于30 Mm,以及具有大于100 Mm^2的强磁剪切(剪切角\geq 80 \degree)的区域。相比之下,FAR的这些参数值大多非常低。Pearson \c{hi} 2检验用于检查SAR和FAR之间差异的显著性,结果表明,这两种类型的AR可以通过这些参数中的每一个来区分。显著性水平分别为99.55%、99.98%、99.98%和99.96%。然而,没有一个参数可以完全区分它们。因此,我们提出了一个综合指数的基础上,这些参数,并发现这两种类型的AR之间的区别也是显着的99.96%的显着性水平。这些结果有助于更好地理解SAR和FAR

英文摘要:

The vector magnetic field characteristics of superactive regions (SARs) hold the key for understanding why SARs are extremely active and provide the guidance in space weather prediction. We aim to quantify the characteristics of SARs using the vector magnetograms taken by the Solar Magnetic Field Telescope at Huairou Solar Observatory Station. The vector magnetic field characteristics of 14 SARs in solar cycles 22 and 23 were analyzed using the following four parameters: 1) the magnetic flux imbalance between opposite polarities, 2) the total photospheric free magnetic energy, 3) the length of the magnetic neutral line with its steep horizontal magnetic gradient, and 4) the area with strong magnetic shear. Furthermore, we selected another eight large and inactive active regions (ARs), which are called fallow ARs (FARs), to compare them with the SARs. We found that most of the SARs have a net magnetic flux higher than 7.0\times10^21 Mx, a total photospheric free magnetic energy higher than 1.0\times10^24 erg/cm, a magnetic neutral line with a steep horizontal magnetic gradient (\geq 300 G/Mm) longer than 30 Mm, and an area with strong magnetic shear (shear angle \geq 80\degree) greater than 100 Mm^2. In contrast, the values of these parameters for the FARs are mostly very low. The Pearson \c{hi}2 test was used to examine the significance of the difference between the SARs and FARs, and the results indicate that these two types of ARs can be fairly distinguished by each of these parameters. The significance levels are 99.55%, 99.98%, 99.98%, and 99.96%, respectively. However, no single parameter can distinguish them perfectly. Therefore we propose a composite index based on these parameters, and find that the distinction between the two types of ARs is also significant with a significance level of 99.96%. These results are useful for a better physical understanding of the SAR and FAR

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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