TEST OF THE HEMISPHERIC RULE OF MAGNETIC HELICITY IN THE SUN USING THE HELIOSEISMIC AND MAGNETIC IMAGER (HMI) DATA
TEST OF THE HEMISPHERIC RULE OF MAGNETIC HELICITY IN THE SUN USING THE HELIOSEISMIC AND MAGNETIC IMAGER (HMI) DATA
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DOI：
10.1088/2041-8205/783/1/l1
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发表时间：
2014-02
期刊：
影响因子：
--
通讯作者：
Y. Liu;J. Hoeksema;X. Sun
中科院分区：
文献类型：
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作者：
Y. Liu;J. Hoeksema;X. Sun
人们发现太阳活动区（AR）的磁扭曲在符号上具有半球偏好（半球规则）：在北方半球为负，在南半球为正。在以前的研究中报道的偏好范围很大，从58%到82%。在这项研究中，我们使用日震和磁成像仪拍摄的矢量磁场数据来检验这种半球偏好，发现所研究的151个AR中有75% ± 7%遵守半球规则，完全在以前研究的偏好范围内。如果将样本分为两组--具有相同符号的磁扭曲和扭动的AR和具有相反符号的AR--则半球偏好的强度有很大差异：前者为64% ± 11%，后者为87% ± 8%。在具有简单双极磁配置的82个AR的子样本中，这种差异变得更加显著：对于具有相同扭曲和扭动符号的AR为56% ± 16%，对于具有相反符号的AR为93%，置信下限和置信上限分别为80%和98%。此处报告的误差为95%置信区间。这可能表明，在磁管出现之前，扭曲的符号没有半球偏好，或者扭曲相对较弱。
Magnetic twist in solar active regions (ARs) has been found to have a hemispheric preference in sign (hemisphere rule): negative in the northern hemisphere and positive in the southern. The preference reported in previous studies ranges greatly, from ∼ 58% to 82%. In this study, we examine this hemispheric preference using vector magnetic field data taken by Helioseismic and Magnetic Imager and find that 75% ± 7% of 151 ARs studied obey the hemisphere rule, well within the preference range in previous studies. If the sample is divided into two groups—ARs having magnetic twist and writhe of the same sign and having opposite signs—the strength of the hemispheric preference differs substantially: 64% ± 11% for the former group and 87% ± 8% for the latter. This difference becomes even more significant in a sub-sample of 82 ARs having a simple bipole magnetic configuration: 56% ± 16% for the ARs having the same signs of twist and writhe, and 93% with lower and upper confidence bounds of 80% and 98% for the ARs having the opposite signs. The error reported here is a 95% confidence interval. This may suggest that, prior to emergence of magnetic tubes, either the sign of twist does not have a hemispheric preference or the twist is relatively weak.