Is Pre-Eruptive Null Point Reconnection Required for Triggering Eruptions?
Is Pre-Eruptive Null Point Reconnection Required for Triggering Eruptions?
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DOI：
10.1007/s11207-006-0173-7
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发表时间：
2006-08
期刊：
影响因子：
2.8
通讯作者：
Hui Li;B. Schmieder;G. Aulanier;A. Berlicki
中科院分区：
文献类型：
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作者：
Hui Li;B. Schmieder;G. Aulanier;A. Berlicki
利用法国-意大利THEMIS望远镜、太阳和日光层天文台（SOHO）的迈克尔逊多普勒成像仪（MDI）、怀柔太阳观测站（HSOS）的太阳磁场望远镜（SMFT）、过渡区和日冕探测器（TRACE）光球磁场的三维（3D）外推，假设一个位场配置，揭示了存在两个磁零点在日冕活动区上方。我们看看他们在触发主耀斑的作用，通过使用在TRACE 1600图像中观察到的明亮的补丁作为示踪剂在太阳表面的能量释放与磁重联在零点。耀斑前观测到的所有亮斑都对应于低空零点。它们与X1.2耀斑没有直接关系，因为相关的分界线位于远离爆发地点的地方。耀斑前没有亮斑对应于高空零点。我们的结论是，爆发可以触发没有爆发前的日冕零点重联，和零点的存在不是耀斑发生的充分条件。我们认为，这种爆发性耀斑是由于持续的磁通出射、持续的光球运动和沿磁中性线沿着的强切变导致的平衡丧失的结果。活动区上方日冕磁力线的打开应该是3B/X1.2大耀斑的副产品，而不是其触发器。
We study the magnetic field evolution and topology of the active region NOAA 10486 before the 3B/X1.2 flare of October 26, 2003, using observational data from the French–Italian THEMIS telescope, the Michelson Doppler Imager (MDI) onboard Solar and Heliospheric Observatory (SOHO), the Solar Magnetic Field Telescope (SMFT) at Huairou Solar Observation Station (HSOS), and the Transition Region and Coronal Explorer (TRACE). Three dimensional (3D) extrapolation of photospheric magnetic field, assuming a potential field configuration, reveals the existence of two magnetic null points in the corona above the active region. We look at their role in the triggering of the main flare, by using the bright patches observed in TRACE 1600 Å images as tracers at the solar surface of energy release associated with magnetic reconnection at the null points. All the bright patches observed before the flare correspond to the low-altitude null point. They have no direct relationship with the X1.2 flare because the related separatrix is located far from the eruptive site. No bright patch corresponds to the high-altitude null point before the flare. We conclude that eruptions can be triggered without pre-eruptive coronal null point reconnection, and the presence of null points is not a sufficient condition for the occurrence of flares. We propose that this eruptive flare results from the loss of equilibrium due to persistent flux emergence, continuous photospheric motion and strong shear along the magnetic neutral line. The opening of the coronal field lines above the active region should be a byproduct of the large 3B/X1.2 flare rather than its trigger.