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arXiv 0902.2940astro-ph.SR
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非均匀大气中极端非对称Stokes V廓线的成因

Origin of Extremely Asymmetric Stokes V Profiles in an Inhomogeneous Atmosphere

V. A. Sheminova

摘要:

本文研究了太阳光球层中Fe I 630.2nm谱线的Stokes V型异常轮廓的形成。数值2-D MHD模拟的太阳磁粒化的结果用于此。在它们的性质上,具有极不对称性的合成异常轮廓与在网络和网络间区域中以优于1 "的空间分辨率观察到的异常轮廓相似。根据我们的研究结果,在弱混合极性磁场区,异常剖面多沿极性反转线成簇出现。通常,它们位于颗粒和泳道的边缘,有时它们会在具有高速度和磁场强度梯度的强磁场集中附近相遇。结果发现,它们在大颗粒分解和新的磁通量管开始形成的区域中以簇的形式出现。不寻常的$V$轮廓可能有一至六个叶。单瓣和多瓣轮廓具有相同的起源。导致极不对称的轮廓的处理的特征在于沿视线的一个或多个极性反转以及复杂的速度和场强梯度。轮廓波瓣的数量越大,场梯度符号改变的概率越大。因此,在极不对称的$V$分布的形成区域中,磁场应该非常复杂。MHD颗粒模拟的直接结果证实了这一点,该结果表明,在下吃水边缘的速度剪切形成了涡流和湍流。这些过程通过混合场极性,特别是在颗粒的边缘,增加了磁场结构的复杂性。

英文摘要:

The formation of unusually shaped Stokes V profiles of the Fe I 630.2 nm line in the solar photosphere are investigated. The results of numerical 2-D MHD simulation of solar magnetogranulation are used for this. In their properties, the synthetic unusual profiles with extremely asymmetry are similar to the unusual profiles observed with a spatial resolution better than 1" in the network and internetwork regions. According to our results the unusual profiles mostly appear in clusters along the polarity inversion lines in the regions of weak magnetic fields with mixed polarity. As a rule, they are located at the edges of granules and lanes, and sometimes they are met close to strong magnetic field concentrations with high velocity and magnetic field strength gradients. They turned out to appear as clusters in the regions where large granules disintegrate and new magnetic flux tubes begin to form. The unusual $V$ profiles may have from one to six lobes. The one-lobe and multilobe profiles are of the same origin. The processing causing the extreme asymmetry of the profiles are characterized by one or several polarity reversal along the line of sight as well as by complicated velocity and field strength gradients. The greater the number of profile lobes, the greater is the probability of the field gradient sign change. Hence it follows that the magnetic field should be very complicated in the regions of formation of extremely asymmetric $V$ profiles. This is confirmed by immediate results of MHD granulation simulations, which demonstrate the formation of vortices and turbulence by the velocity shear at down draft edges. These processes add complexity to the magnetic field structure by mixing field polarities, particularly at the edges of granules.

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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