Polar Field Reversal Observations with Hinode

Shiota, D.; Tsuneta, S.; Shimojo, M.; Sako, N.; Orozco-Suárez, D.; Ishikawa, R.
Bibliographical reference

The Astrophysical Journal, Volume 753, Issue 2, article id. 157 (2012).

Advertised on:
7
2012
Number of authors
6
IAC number of authors
1
Citations
76
Refereed citations
67
Description
We have been monitoring yearly variation in the Sun's polar magnetic fields with the Solar Optical Telescope aboard Hinode to record their evolution and expected reversal near the solar maximum. All magnetic patches in the magnetic flux maps are automatically identified to obtain the number density and magnetic flux density as a function of the total magnetic flux per patch. The detected magnetic flux per patch ranges over four orders of magnitude (1015-1020 Mx). The higher end of the magnetic flux in the polar regions is about one order of magnitude larger than that of the quiet Sun, and nearly that of pores. Almost all large patches (>=1018 Mx) have the same polarity, while smaller patches have a fair balance of both polarities. The polarity of the polar region as a whole is consequently determined only by the large magnetic concentrations. A clear decrease in the net flux of the polar region is detected in the slow rising phase of the current solar cycle. The decrease is more rapid in the north polar region than in the south. The decrease in the net flux is caused by a decrease in the number and size of the large flux concentrations as well as the appearance of patches with opposite polarity at lower latitudes. In contrast, we do not see temporal change in the magnetic flux associated with the smaller patches (<1018 Mx) and that of the horizontal magnetic fields during the years 2008-2012.
Related projects
Project Image
Magnetism, Polarization and Radiative Transfer in Astrophysics
Magnetic fields pervade all astrophysical plasmas and govern most of the variability in the Universe at intermediate time scales. They are present in stars across the whole Hertzsprung-Russell diagram, in galaxies, and even perhaps in the intergalactic medium. Polarized light provides the most reliable source of information at our disposal for the
Tanausú del
Pino Alemán