J/A+A/539/A13 Solar bipolar magnetic fields (Yamamoto, 2012)
The area asymmetry in bipolar magnetic fields.
Yamamoto T.T.
<Astron. Astrophys. 539, A13 (2012)>
=2012A&A...539A..13Y 2012A&A...539A..13Y
ADC_Keywords: Sun ; Magnetic fields
Keywords: Sun: photosphere - Sun: surface magnetism - Sun: sunspots
Abstract:
The area asymmetry between the preceding and following regions of
opposite magnetic polarity in a bipolar sunspot group has been known
since the studies of Hale and his colleagues in the early 20th
century. This area asymmetry, however, has not yet been investigated
quantitatively using magnetograms.
We quantitatively define the area asymmetry of bipolar magnetic fields
in the photosphere of active regions on the Sun, and investigate
correlations between the area asymmetry and other parameters.
Description:
'Table_3.dat' is the list of bipolar regions. The date (column 1-3),
MDI daily number (column 4), field-weighted position (x, y), area,
average field strengths of the positive field (column 5-8), and those
of the negative field (column 9-12). Morphological parameters in our
paper are derived from these values.
The field-weighted positions (x, y), area, average field strength of
the positive and negative fields are derived from MDI longitudinal
magnetograms.
We analyzed 96 minutes cadence data sets. In these data sets, we
analyzed the magnetogram observed around 00:00 UT on each day. The
pixel width of the magnetograms is 1.98 arcsec.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 77 138 Bipolar regions
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See also:
J/ApJS/169/439 : Models of solar magnetic structures (Socas-Navarro, 2007)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 "YYYY/MM/DD" Date Observation date
12- 15 I4 --- Nset Number of daily data set
17- 22 F6.1 arcsec x+ The field-weighted x of the positive field
24- 29 F6.1 arcsec y+ The field-weighted y of the positive field
32- 39 E8.2 km2 S+ Area of the positive field
41- 46 F6.1 10-4T B+ Average field strength of the positive field
48- 53 F6.1 arcsec x- The field-weighted x of the negative field
55- 60 F6.1 arcsec y- The field-weighted y of the negative field
63- 70 E8.2 km2 S- Area of the negative field
72- 77 F6.1 10-4T B- Average field strength of the negative field
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Acknowledgements:
Testsuya Yamamoto, tyamamot(at)stelab.nagoya-u.ac.jp
(End) T.T. Yamamoto [STEL, Nagoya Univ.], Patricia Vannier [CDS] 16-Jan-2012