The Relationship between Magnetic Gradient and Magnetic Shear in Five Super Active Regions Producing Great Flares
The Relationship between Magnetic Gradient and Magnetic Shear in Five Super Active Regions Producing Great Flares
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DOI：
10.1088/1009-9271/6/4/11
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发表时间：
2006-08
期刊：
影响因子：
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通讯作者：
Haimin Wang;Hui Song;J. Jing;V. Yurchyshyn;Yuanyong Deng;Hongqi Zhang;D. Falconer;Jing Li
中科院分区：
文献类型：
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作者：
Haimin Wang;Hui Song;J. Jing;V. Yurchyshyn;Yuanyong Deng;Hongqi Zhang;D. Falconer;Jing Li
我们研究了产生大耀斑（X5或更大）的五个著名活动区的磁结构。正在调查的六个耀斑是1991年6月9日AR 6659的X12耀斑，2000年7月14日AR 9077的X5.7耀斑，2001年4月6日AR 9415的X5.6耀斑，2001年8月25日AR 9591的X5.3耀斑，2003年10月28日的X17耀斑和2003年10月29日的X10耀斑，都在AR 10486中。最后五个事件都有相应的LASCO观测，并且都与Halo CME有关。分析了大熊座太阳观测站、怀柔太阳观测站、马歇尔航天飞行中心和米斯太阳观测站的矢量磁图。特别是，我们研究了磁梯度来自视线磁图和磁剪切来自矢量磁图，并发现这两个参数之间的明显的相关性在约90%的水平。我们发现，磁梯度可能是一个更好的代理比剪切预测一个主要的耀斑可能会发生：所有六个耀斑发生在中性线与最大梯度。耀斑中性线的平均梯度范围为0.14至0.50 G km−1，是活动区所有中性线平均值的2.3至8倍。如果我们使用磁剪切作为代理，在六个事件中，至少有一个，可能是两个事件中的耀斑中性线将被错误识别。
We study the magnetic structure of five well-known active regions that produced great flares (X5 or larger). The six flares under investigation are the X12 flare on 1991 June 9 in AR 6659, the X5.7 flare on 2000 July 14 in AR 9077, the X5.6 flare on 2001 April 6 in AR 9415, the X5.3 flare on 2001 August 25 in AR 9591, the X17 flare on 2003 October 28 and the X10 flare on 2003 October 29, both in AR 10486. The last five events had corresponding LASCO observations and were all associated with Halo CMEs. We analyzed vector magnetograms from Big Bear Solar Observatory, Huairou Solar Observing Station, Marshall Space Flight Center and Mees Solar Observatory. In particular, we studied the magnetic gradient derived from line-of-sight magnetograms and magnetic shear derived from vector magnetograms, and found an apparent correlation between these two parameters at a level of about 90%. We found that the magnetic gradient could be a better proxy than the shear for predicting where a major flare might occur: all six flares occurred in neutral lines with maximum gradient. The mean gradient of the flaring neutral lines ranges from 0.14 to 0.50 G km−1, 2.3 to 8 times the average value for all the neutral lines in the active regions. If we use magnetic shear as the proxy, the flaring neutral line in at least one, possibly two, of the six events would be mis-identified.