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arXiv 0910.0786astro-ph.SR
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STEREO观测到的暗条消失事件的三维演化

3D evolution of a filament disappearance event observed by STEREO

S. Gosain, B. Schmieder, P. Venkatakrishnan, R. Chandra, G. Artzner

摘要:

2008年5月22日,在我们最近的活动JOP 178期间观察到细丝消失事件。位于南半球的丝状体具有左旋手性,符合半球规则。这一事件被几个天文台,特别是THEMIS观测到。在消失前一天,H $α$观测显示沿着暗条的相邻位置有上下流动,这表明等离子体沿着扭曲的通量绳运动。THEMIS和GONG的观测显示,剪切光球运动导致倒刺周围的磁通量抵消。STEREO A,B航天器与分离角52.4度,显示了相当不同的看法,这untwisting通量绳在He II 304的图像。在这里,我们重建的三维几何形状的灯丝在其喷发阶段,使用STEREO EUV He II 304毫米的图像,发现灯丝是高度倾斜的太阳法线。He II 304射电望远镜的影像显示了在快速演化阶段中的单个线,这些线以约100 km s $^{-1}$的视速度振荡并上升到约120 Mm的高度。最后,当磁绳膨胀到日冕中时,灯丝会变得光学上很薄,以至于无法检测到。STEREO没有探测到CME,LASCO只在02:00 UT的消失相开始时记录到一个微弱的CME,这可能是由于部分暗条喷发造成的。此外,STEREO Fe XII 195磁共振图像显示,在消失阶段之前,灯丝下方有明亮的环,表明磁通绳下方有磁重联。

英文摘要:

A filament disappearance event was observed on 22 May 2008 during our recent campaign JOP 178. The filament, situated in the southern hemisphere, showed sinistral chirality consistent with the hemispheric rule. The event was well observed by several observatories in particular by THEMIS. One day before the disappearance, H$α$ observations showed up and down flows in adjacent locations along the filament, which suggest plasma motions along twisted flux rope. THEMIS and GONG observations show shearing photospheric motions leading to magnetic flux canceling around barbs. STEREO A, B spacecraft with separation angle 52.4 degrees, showed quite different views of this untwisting flux rope in He II 304 Å images. Here, we reconstruct the 3D geometry of the filament during its eruption phase using STEREO EUV He II 304 Å images and find that the filament was highly inclined to the solar normal. The He II 304 Å movies show individual threads, which oscillate and rise to an altitude of about 120 Mm with apparent velocities of about 100 km s$^{-1}$, during the rapid evolution phase. Finally, as the flux rope expands into the corona, the filament disappears by becoming optically thin to undetectable levels. No CME was detected by STEREO, only a faint CME was recorded by LASCO at the beginning of the disappearance phase at 02:00 UT, which could be due to partial filament eruption. Further, STEREO Fe XII 195 Å images showed bright loops beneath the filament prior to the disappearance phase, suggesting magnetic reconnection below the flux rope.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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