Horizontal flow fields in and around a small active region-- The transition period between flux emergence and decay
Horizontal flow fields in and around a small active region-- The transition period between flux emergence and decay
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DOI：
10.1051/0004-6361/201628380
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发表时间：
2016-05
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通讯作者：
M. Verma;C. Denker;H. Balthasar;C. Kuckein;S. J. G. Manrique;M. Sobotka;N. B. Gonz'alez;S. Hoch;A. Diercke;P. Kummerow;T. Berkefeld;M. Collados;A. Feller;A. Hofmann;F. Kneer;A. Lagg;J. Lohner-Bottcher;H. Nicklas;A. P. Yabar;R. Schlichenmaier;D. Schmidt;W. Schmidt;M. Schubert;M. Sigwarth;S. Solanki;D. Soltau;J. Staude;K. Strassmeier;R. Volkmer;O. V. D. Luhe;T. Waldmann
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文献类型：
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作者：
M. Verma;C. Denker;H. Balthasar;C. Kuckein;S. J. G. Manrique;M. Sobotka;N. B. Gonz'alez;S. Hoch;A. Diercke;P. Kummerow;T. Berkefeld;M. Collados;A. Feller;A. Hofmann;F. Kneer;A. Lagg;J. Lohner-Bottcher;H. Nicklas;A. P. Yabar;R. Schlichenmaier;D. Schmidt;W. Schmidt;M. Schubert;M. Sigwarth;S. Solanki;D. Soltau;J. Staude;K. Strassmeier;R. Volkmer;O. V. D. Luhe;T. Waldmann
目标。将高分辨率观测与天气观测相结合，旨在全面描述光球层通量的出现以及最终形成成熟活动区的增长过程。方法.小活动区NOAA 12118于2014年7月18日被1.5米的格里戈尔太阳望远镜观测到。在GREGOR法布里-珀罗干涉仪（GFPI）的蓝色成像通道（BIC）中获得的高分辨率时间序列的蓝色连续谱和G波段图像由SDO机载HMI获得的LOS磁图和连续谱图像补充。水平自行和水平等离子体速度分别用局部相关跟踪（LCT）和微分仿射速度估计器计算。采用形态学图像处理方法测量EFR在其演变过程中的光/磁面积、磁通量和分离轮廓。结果计算出的光度区、磁区和磁通量的增长率大约是各自衰减率的两倍。使用HMI五天磁图的时空图描绘了一个叶状结构，这是由两个极性的初始分离，快速扩张阶段，蔓延停滞的时间和区域再次缓慢收缩的时期决定的。在初始阶段，0.26km\s的分离速率最大，当分离停止时，分离速率减小。水平等离子体速度计算在四个演变阶段表明不断变化的模式的流入。在LCT地图中，我们发现持续的流动模式，如向外运动的两个主要的孔，一个发散的功能附近的拖尾孔标记的网站上涌的等离子体和通量的出现，和低速度在内部的孔。我们在两个主要极性之间检测到许多细长的快速膨胀颗粒。
Aims. Combining high-resolution and synoptic observations aims to provide a comprehensive description of flux emergence at photospheric level and of the growth process that eventually leads to a mature active region. Methods. Small active region NOAA 12118 was observed on 2014 July 18 with the 1.5-meter GREGOR solar telescope on 2014 July 18. High-resolution time-series of blue continuum and G-band images acquired in the blue imaging channel (BIC) of the GREGOR Fabry-Perot Interferometer (GFPI) were complemented by LOS magnetograms and continuum images obtained with the HMI onboard the SDO. Horizontal proper motions and horizontal plasma velocities were computed with local correlation tracking (LCT) and the differential affine velocity estimator, respectively. Morphological image processing was employed to measure the photometric/magnetic area, magnetic flux, and the separation profile of the EFR during its evolution. Results. The computed growth rates for photometric area, magnetic area, and magnetic flux are about twice as high as the respective decay rates. The space-time diagram using HMI magnetograms of five days traces a leaf-like structure, which is determined by the initial separation of the two polarities, a rapid expansion phase, a time when the spread stalls, and a period when the region slowly shrinks again. The separation rate of 0.26 km\s is highest in the initial stage, and it decreases when the separation comes to a halt. Horizontal plasma velocities computed at four evolutionary stages indicate a changing pattern of inflows. In LCT maps we find persistent flow patterns such as outward motions in the outer part of the two major pores, a diverging feature near the trailing pore marking the site of upwelling plasma and flux emergence, and low velocities in the interior of pores. We detected many elongated rapidly expanding granules between the two major polarities.