Issue |
A&A
Volume 428, Number 2, December III 2004
|
|
---|---|---|
Page(s) | 613 - 628 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361:20040436 | |
Published online | 26 November 2004 |
Solar magnetic elements at 0
1 resolution*
General appearance and magnetic structure
1
Lockheed Martin Solar and Astrophysics Lab, 3251 Hanover St., Palo Alto, California 94304, USA e-mail: berger@lmsal.com
2
Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, 0315 Oslo, Norway
3
The Institute for Solar Physics of the Royal Swedish Academy of Sciences, Alba Nova University Center, 10691 Stockholm, Sweden
4
Center of Mathematics for Applications, University of Oslo, PO Box 1053 Blindern, 0316 Oslo, Norway
Received:
13
March
2004
Accepted:
27
August
2004
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 ~70 km (01) structures
and find new forms of magnetic structures in this particular
region. A cotemporal
H-line image is used to examine
the low-chromosphere of network elements. A cotemporal
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
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.
Key words: Sun: magnetic fields / convection
© ESO, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.