Sunspot splitting triggering an eruptive flare
Sunspot splitting triggering an eruptive flare
复制标题
DOI：
10.1051/0004-6361/201321106
复制
发表时间：
2013-11
影响因子：
6.5
通讯作者：
R. Louis;K. Puschmann;B. Kliem;H. Balthasar;C. Denker
中科院分区：
文献类型：
--
作者：
R. Louis;K. Puschmann;B. Kliem;H. Balthasar;C. Denker
目标。我们研究了2012年7月2日在活跃区域NOAA 11515中，太阳主黑子的分裂和相关通量的出现和消除是如何引起M5.6级耀斑爆发的。方法。利用日震和磁成像仪的连续强度、视距磁图和多普勒图资料分析了光球演化过程。位于特内里费岛泰德天文台的色球望远镜的H α和He 10830埃滤光图跟踪了耀斑的演变。对应的日冕条件由大气成像组件的171埃和304埃图像得到。利用局部相关跟踪来确定剪切流。结果。新出现的通量在太阳黑子和新的卫星黑子前面形成一条中性线。太阳黑子的分裂导致了一股持久的流向这条中性线，在那里形成了细丝。进一步的通量出现，部分是混合极性，以及在中性线反复发生通量取消的事件。随着附近的c级前体耀斑与长丝相互作用的迹象，长丝几乎与M5.6耀斑同时爆发，并演变成日冕物质抛射。太阳黑子在没有形成光桥的情况下伸展，分裂得异常快（大约在一天内，大约在喷发后6小时完成），分裂成两个几乎相等的部分。它的前半部分强烈地从活动区分离出来，接近邻近的活动区，在那里它所有的日冕磁连接都是扎根的。它还快速旋转（4.9度h(-1)），并在其边缘引起了显著的剪切流。结论。这次喷发是由（亚）光球和日冕的一系列复杂过程引起的。向中性线的持续流动可能导致形成了固定长丝的通量绳。这些流动及其相关的通量抵消、新出现的通量和前体耀斑都导致了通量绳的不稳定。我们把太阳黑子的分裂解释为两个不同的通量束的分离，它们不同地根植于对流区，只是暂时地与黑子结合。这解释了旋转是分离通量的持续上升，这意味着至少太阳黑子的这一部分仍然与它在对流区深处的根相连。
Aims. We investigate how the splitting of the leading sunspot and associated flux emergence and cancellation in active region NOAA 11515 caused an eruptive M5.6 flare on 2012 July 2. Methods. Continuum intensity, line-of-sight magnetogram, and dopplergram data of the Helioseismic and Magnetic Imager were employed to analyse the photospheric evolution. Filtergrams in H alpha and He I 10830 angstrom of the Chromospheric Telescope at the Observatorio del Teide, Tenerife, track the evolution of the flare. The corresponding coronal conditions were derived from 171 angstrom and 304 angstrom images of the Atmospheric Imaging Assembly. Local correlation tracking was utilized to determine shear flows. Results. Emerging flux formed a neutral line ahead of the leading sunspot and new satellite spots. The sunspot splitting caused a long-lasting flow towards this neutral line, where a filament formed. Further flux emergence, partly of mixed polarity, as well as episodes of flux cancellation occurred repeatedly at the neutral line. Following a nearby C-class precursor flare with signs of interaction with the filament, the filament erupted nearly simultaneously with the onset of the M5.6 flare and evolved into a coronal mass ejection. The sunspot stretched without forming a light bridge, splitting unusually fast (within about a day, complete approximate to 6 h after the eruption) in two nearly equal parts. The front part separated strongly from the active region to approach the neighbouring active region where all its coronal magnetic connections were rooted. It also rotated rapidly (by 4.9 degrees h(-1)) and caused significant shear flows at its edge. Conclusions. The eruption resulted from a complex sequence of processes in the (sub-)photosphere and corona. The persistent flows towards the neutral line likely caused the formation of a flux rope that held the filament. These flows, their associated flux cancellation, the emerging flux, and the precursor flare all contributed to the destabilization of the flux rope. We interpret the sunspot splitting as the separation of two flux bundles differently rooted in the convection zone and only temporarily joined in the spot. This explains the rotation as the continued rise of the separating flux, and it implies that at least this part of the sunspot was still connected to its roots deep in the convection zone.