Inference of chromospheric magnetic fields in a sunspot derived from spectropolarimetry of Ca II 8542 A [SSA]

http://arxiv.org/abs/1712.06829


We analyze spectropolarimetric observations of the chromospheric Ca II 8542 A line taken by the Interferometric Bidimensional Spectrometer (IBIS) at the Dunn Solar Telescope. The data were observed on 2012 January 29 for the NOAA active region 11408. Adopting the center-of-gravity (COG) approach we obtain the line-of-sight (LOS) field strength for the chromospheric IBIS data of Ca II 8542 A line. The LOS strength of the magnetic field is determined in the target active region inside a field of view 45 x 95 arcsec. The LOS field values were found to be increase up to 800 G inside the umbral region and decrease systematically toward the edges of a sunspot. Under the weak field approximation (WFA), the horizontal, vertical magnetic field components and azimuthal field vector are obtained.

Read this paper on arXiv…

A. Abdelkawy, A. Shaltout, M. Beheary, et. al.
Wed, 20 Dec 17
71/83

Comments: 12 pages, 6 figures