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arXiv 0712.2663astro-ph
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宁静太阳颗粒中的磁场出现

Magnetic field emergence in quiet Sun granules

D. Orozco Suarez, L. R. Bellot Rubio, J. C. del Toro Iniesta, S. Tsuneta

摘要:

我们描述了一种新形式的小尺度磁通量出现在安静的太阳。这一过程似乎将太阳内部的垂直磁场带到光球层,在光球层,磁场出现在颗粒状对流单体的上方。本文分析了Hinode在盘中心附近的一个安静区域获得的高节奏时间序列的偏振光谱测量。我们从观测到的斯托克斯轮廓提取线参数,并研究它们随时间的演化。从观察到的\ion{Fe}{i} 630 nm线导出的圆偏振图显示在颗粒细胞中心出现的清晰的磁信号。我们没有发现任何证据,线性偏振信号与这些事件。磁通量斑块随时间增长,占据颗粒区域的很大一部分。然后信号逐渐消失,直到它们完全消失。这些事件的典型寿命大约为20分钟。没有显着的变化,色球似乎发生在响应的出现,所揭示的同空间\ion{Ca}{ii} H滤波图。在新兴的通量浓度测量的斯托克斯I和V配置文件显示出强烈的不对称性和多普勒频移。这些事件的起源目前尚不清楚,但我们认为,它们可能代表垂直场线从光球底部的出现,可能被颗粒的对流上升流拖动。斯托克斯光谱的初步反演表明,这种情况是与观测兼容。然而,垂直磁力线的出现并非没有概念上的问题。

英文摘要:

We describe a new form of small-scale magnetic flux emergence in the quiet Sun. This process seems to take vertical magnetic fields from the solar interior to the photosphere, where they appear above granular convection cells. High-cadence time series of spectropolarimetric measurements obtained by Hinode in a quiet region near disk center are analyzed. We extract line parameters from the observed Stokes profiles and study their evolution with time. The circular polarization maps derived from the observed \ion{Fe}{i} 630 nm lines show clear magnetic signals emerging at the center of granular cells. We do not find any evidence for linear polarization signals associated with these events. The magnetic flux patches grow with time, occupying a significant fraction of the granular area. The signals then fade until they disappear completely. The typical lifetime of these events is of the order of 20 minutes. No significant changes in the chromosphere seem to occur in response to the emergence, as revealed by co-spatial \ion{Ca}{ii} H filtergrams. The Stokes I and V profiles measured in the emerging flux concentrations show strong asymmetries and Doppler shifts. The origin of these events is unclear at present, but we suggest that they may represent the emergence of vertical fields lines from the bottom of the photosphere, possibly dragged by the convective upflows of granules. Preliminary inversions of the Stokes spectra indicate that this scenario is compatible with the observations. The emergence of vertical field lines is not free from conceptual problems, though.

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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