Hinode observations of magnetic elements in internetwork areas

被引:71
作者
De Wijn, A. G. [1 ]
Lites, B. W. [1 ]
Berger, T. E. [2 ]
Frank, Z. A. [2 ]
Tarbell, T. D. [2 ]
Ishikawa, R. [3 ]
机构
[1] Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA
[2] Lockheed Martin Solar & Astrophys Lab, Palo Alto, CA 94304 USA
[3] Univ Tokyo, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan
基金
英国科学技术设施理事会;
关键词
Sun : granulation; Sun : magnetic fields; Sun : photosphere;
D O I
10.1086/590237
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We use sequences of images and magnetograms from Hinode to study magnetic elements in internetwork parts of the quiet solar photosphere. Visual inspection shows the existence of many long-lived ( several hours) structures that interact frequently and may migrate over distances of similar to 7 Mm over a period of a few hours. About a fifth of the elements have an associated bright point in G-band or Ca II H intensity. We apply a hysteresis-based algorithm to identify elements. The algorithm is able to track elements for about 10 minutes on average. Elements intermittently drop below the detection limit, although the associated flux apparently persists and often reappears some time later. We infer proper motions of elements from their successive positions and find that they obey a Gaussian distribution with an rms of 1.57 +/- 0.08 km s(-1). The apparent flows indicate a bias of about 0.2 km s(-1) toward the network boundary. Elements of negative polarity show a higher bias than elements of positive polarity, perhaps as a result of the dominant positive polarity of the network in the field of view or because of increased mobility due to their smaller size. A preference for motions in X is likely explained by higher supergranular flow in that direction. We search for emerging bipoles by grouping elements of opposite polarity that appear close together in space and time. We find no evidence supporting Joy's law at arcsecond scales.
引用
收藏
页码:1469 / 1476
页数:8
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