Magnetic Causes of the Eruption of a Quiescent Filament
Magnetic Causes of the Eruption of a Quiescent Filament
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DOI：
10.1007/s11207-007-9100-9
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发表时间：
2008-02
期刊：
影响因子：
2.8
通讯作者：
B. Schmieder;V. Bommier;R. Kitai;T. Matsumoto;T. Ishii;M. Hagino;H. Li;L. Golub
中科院分区：
文献类型：
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作者：
B. Schmieder;V. Bommier;R. Kitai;T. Matsumoto;T. Ishii;M. Hagino;H. Li;L. Golub
在2006年8月的JOP178活动期间，我们在三天的观察时间（8月24日至8月26日）后观察到我们的目标（位于S25°的大型静止细丝）消失了。多波长仪器正在运行：THEMIS/MTR（“MulTi-Raies”）矢量磁力仪、171 Å 和 1600 Å 的 TRACE（“过渡区和日冕探测器”）以及 Hida 无穹顶太阳望远镜。在喷发前 24 小时以上，检测到细丝中的逆流气流 (+/-10 km s−1)。在此期间，全球结构开始缓慢上升，速度估计为 1 km s−1 量级。在喷发前一小时（世界标准时间 8 月 26 日 09:00 左右），速度达到 5 km s−1。 LASCO 在 8 月 26 日世界标准时间 21:00 左右观察到日冕物质抛射缓慢，怀疑是灯丝喷发造成的。即使 THEMIS 具有高偏振灵敏度，也没有检测到 Hα 或冠状线变亮，灯丝通道中没有新出现的极性。我们测量到网络的光球磁场强度相对较大地下降（从 400 G 到 100 G），其向下的磁张力为下面受应力的灯丝磁场提供了稳定性。根据一些基于湍流光球扩散的 MHD 模型，这种磁场强度（张力）的温和降低可能充当不稳定机制，首先导致细丝缓慢上升并快速喷发。
During the JOP178 campaign in August 2006, we observed the disappearance of our target, a large quiescent filament located at S25°, after an observation time of three days (24 August to 26 August). Multi-wavelength instruments were operating: THEMIS/MTR (“MulTi-Raies”) vector magnetograph, TRACE (“Transition Region and Coronal Explorer”) at 171 Å and 1600 Å and Hida Domeless Solar telescope. Counter-streaming flows (+/−10 km s−1) in the filament were detected more than 24 hours before its eruption. A slow rise of the global structure started during this time period with a velocity estimated to be of the order of 1 km s−1. During the hour before the eruption (26 August around 09:00 UT) the velocity reached 5 km s−1. The filament eruption is suspected to be responsible for a slow CME observed by LASCO around 21:00 UT on 26 August. No brightening in Hα or in coronal lines, no new emerging polarities in the filament channel, even with the high polarimetry sensitivity of THEMIS, were detected. We measured a relatively large decrease of the photospheric magnetic field strength of the network (from 400 G to 100 G), whose downward magnetic tension provides stability to the underlying stressed filament magnetic fields. According to some MHD models based on turbulent photospheric diffusion, this gentle decrease of magnetic strength (the tension) could act as the destabilizing mechanism which first leads to the slow filament rise and its fast eruption.