Recovering the Line-Of-Sight Magnetic Field in the Chromosphere from Ca II IR Spectra

We propose a method to derive the line-of-sight magnetic flux density from measurements in the chromospheric Ca II IR line at 854.2 nm. The method combines two well-understood techniques, the center-of-gravity and bisector methods, in a single hybrid technique. The technique is tested with magneto-static simulations of a flux tube. We apply the method to observations with the Interferometric Bidimensional Spectrometer (IBIS) installed at the Dunn Solar Telescope of the NSO/SP to investigate the morphology of the lower chromosphere, with focus on the chromospheric counterparts to the underlying photospheric magnetic flux elements.
Comment: to appear in Memorie della Societa' Astronomica Italiana, 2010, eds. A. Tritschler and K. Reardon