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arXiv 1209.0983astro-ph.SR
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三角洲太阳黑子耀斑活动期间的异常Stokes V廓线

Unusual Stokes V profiles during flaring activity of a delta sunspot

C. E. Fischer, C. U. Keller, F. Snik, L. Fletcher, H. Socas-Navarro

摘要:

我们分析了一组全斯托克斯轮廓观测耀斑活动区NOAA 10808与矢量谱磁仪(VSM)的SOLIS设施。我们的目标是量化磁场和速度场的瞬态和永久变化。将结果与MDI磁图和重建的RHESSI X射线图像相结合。我们发现耀斑期间光球磁场的重组迹象接近极性反转线(PIL)的耀斑网站。在本影中的两个位置,我们遇到了强场(约。3 kG),这是从斯托克斯I分布推断的,然而,斯托克斯I分布表现出低偏振信号。在耀斑期间,我们观察到另外不对称的斯托克斯V轮廓在这些网站之一。非对称的斯托克斯V轮廓出现同空间和同时间的MDI磁图和色球硬X射线源观察到一个强大的明显的极性反转。非对称Stokes剖面的两分量大气拟合导致视线速度差在约1000 m的范围内。在光球中,两个分量之间的速度为12 km/s至14 km/s。另一种可能性是,局部大气加热导致观察到的不对称斯托克斯V型轮廓形状。在这两种情况下,我们的分析表明,一个非常局部的补丁约。5角秒的光球本影,与耀斑的足迹点共空间,表现出亚分辨率的精细结构。

英文摘要:

We analyze a set of full Stokes profile observations of the flaring active region NOAA 10808 recorded with the Vector-Spectromagnetograph (VSM) of the SOLIS facility. We aim to quantify transient and permanent changes in the magnetic field and velocity field. The results are put in context with MDI magnetograms and reconstructed RHESSI X-ray images. We find signs of restructuring of the photospheric magnetic field during the flare close to the polarity inversion line (PIL) at the flaring site. At two locations in the umbra we encounter strong fields (approx. 3 kG), as inferred from the Stokes I profiles which, however, exhibit a low polarization signal. During the flare we observe in addition asymmetric Stokes V profiles at one of these sites. The asymmetric Stokes V profiles appear co-spatial and co-temporal with a strong apparent polarity reversal observed in MDI-magnetograms and a chromospheric hard X-ray source. The two-component atmosphere fits of the asymmetric Stokes profiles result in line-of-sight velocity differences in the range of approx. 12km/s to 14 km/s between the two components in the photosphere. Another possibility is that local atmospheric heating is causing the observed asymmetric Stokes V profile shape. In either case our analysis shows that a very localized patch of approx. 5 arcsec in the photospheric umbra, co-spatial with a flare footpoint, exhibits a sub-resolution fine structure.

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