WHY IS A FLARE-RICH ACTIVE REGION CME-POOR?
WHY IS A FLARE-RICH ACTIVE REGION CME-POOR?
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DOI：
10.3847/0004-637x/826/2/119
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Lijuan Liu;Yuming Wang;Jingxiu Wang;C. Shen;P. Ye;Rui Liu;Jun Chen;Quanhao Zhang;S. Wang
中科院分区：
文献类型：
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作者：
Lijuan Liu;Yuming Wang;Jingxiu Wang;C. Shen;P. Ye;Rui Liu;Jun Chen;Quanhao Zhang;S. Wang
太阳活动区（AR）是两种最剧烈的太阳爆发的主要来源，即耀斑和日冕物质抛射（CME）。过去24年来最大的AR，NOAA AR 12192，于2014年10月17日至30日穿过可见盘，异常地产生了100多个耀斑，其中包括32个M级和6个X级，但只有一个小型CME。耀斑和日冕物质抛射被认为是同一喷发过程中的两种现象。为什么这样一个耀斑丰富的AR如此CME贫乏？我们比较了这个AR与其他四个AR;两个都是生产性的，两个是惰性的。根据SDO/HMI矢量磁象图对光球参数的研究表明，富耀斑的AR 12192与其他两个生产性AR一样，具有比两个惰性AR更大的磁通量、电流和自由磁能，但与两个生产性AR相反，它沿耀斑中性线沿着没有强的、集中的电流螺旋度，这表明不存在由高度剪切或扭曲的磁力线组成的成熟磁结构。此外，AR 12192以上的衰减指数相对较低，显示出较强的约束。这些结果表明，生产AR总是大，有足够的电流和自由能的动力耀斑，但是否耀斑是伴随着CME似乎是相关的（1）存在一个成熟的剪切或扭曲的核心领域作为种子的CME，或（2）足够弱的约束覆盖拱廊。
Solar active regions (ARs) are the major sources of two of the most violent solar eruptions, namely flares and coronal mass ejections (CMEs). The largest AR in the past 24 years, NOAA AR 12192, which crossed the visible disk from 2014 October 17 to 30, unusually produced more than one hundred flares, including 32 M-class and 6 X-class ones, but only one small CME. Flares and CMEs are believed to be two phenomena in the same eruptive process. Why is such a flare-rich AR so CME-poor? We compared this AR with other four ARs; two were productive in both and two were inert. The investigation of the photospheric parameters based on the SDO/HMI vector magnetogram reveals that the flare-rich AR 12192, as with the other two productive ARs, has larger magnetic flux, current, and free magnetic energy than the two inert ARs but, in contrast to the two productive ARs, it has no strong, concentrated current helicity along both sides of the flaring neutral line, indicating the absence of a mature magnetic structure consisting of highly sheared or twisted field lines. Furthermore, the decay index above the AR 12192 is relatively low, showing strong constraint. These results suggest that productive ARs are always large and have enough current and free energy to power flares, but whether or not a flare is accompanied by a CME is seemingly related to (1) the presence of a mature sheared or twisted core field serving as the seed of the CME, or (2) a weak enough constraint of the overlying arcades.