Solar magnetic elements at 0′.′1 resolution -: General appearance and magnetic structure

被引:122
作者
Berger, TE
van der Voort, LHMR
Löfdahl, MG
Carlsson, M
Fossum, A
Hansteen, VH
Marthinussen, E
Title, A
Scharmer, G
机构
[1] Lockheed Martin Solar & Astrophys Lab, Palo Alto, CA 94304 USA
[2] Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway
[3] Alba Nova Univ Ctr, Royal Swedish Acad Sci, Inst Solar Phys, S-10691 Stockholm, Sweden
[4] Univ Oslo, Ctr Math Applicat, N-0316 Oslo, Norway
关键词
Sun : magnetic fields; convection;
D O I
10.1051/0004-6361:20040436
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
New observations of solar magnetic elements in a remnant active region plage near disk center are presented. The observations were obtained at the recently commissioned Swedish 1-m Solar Telescope on La Palma. We examine a single 430.5 nm G-band filtergram that resolves similar to70 km (0."1) structures and find new forms of magnetic structures in this particular region. A cotemporal Ca II H-line image is used to examine the low-chromosphere of network elements. A cotemporal Fe. 630.25 nm magnetogram that resolves structures as small as 120 km (0."18) FWHM with a flux sensitivity of approximately 130 Mx cm(-2) quantifies the magnetic structure of the region. A Ni I 676.8 nm Dopplergram establishes relative velocity patterns associated with the network features with an accuracy of about 300 m s(-1). We find that magnetic flux in this region as seen in both the magnetogram and the G-band image is typically structured into larger, amorphous, "ribbons" which are not resolved into individual flux tubes. The measured magnetic flux density in the ribbon structures ranges from 300 to 1500 Mx cm-2, the higher values occurring at localized concentrations embedded within the ribbons. The Dopplergram indicates relative downflows associated with all magnetic elements with some indication that higher downflows occur adjacent to the peak magnetic flux location. The mean absolute magnetic flux density of the remnant plage network is about 130 Mx cm(-2); in the lowest flux regions of the field-of-view, the mean absolute flux density is approximately 60 Mx cm(-2). Within these quiet regions we do not find evidence of pervasive kilo-gauss strength magnetic elements as seen in recent high resolution internetwork studies. In general, the observations confirm recent 3-dimensional numerical simulations which show that the magnetic field in high-density regions such as plage is concentrated in complex structures that are not generally composed of discrete magnetic flux tubes.
引用
收藏
页码:613 / U101
页数:19
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