Abstract Details

Name: Nagaraju Krishnappa
Affiliation: Indian Institute of Astrophysics
Conference ID: ASI2020_293
Title : Sunspot magnetometry in Hα and Ca II 854.2 nm spectral lines
Authors and Co-Authors : K. Nagaraju, Harsh Mathur, Hemanth Pruthvi, Ramesh Kumar, K. Sankarasubramanian and K. E. Rangarajan
Abstract Type : Oral
Abstract Category : Sun and the Solar System
Abstract : Spectropolarimetric observations of two sunspots in Hα and one sunspot in Ca II 854.2 nm have been carried out at Kodaikanal Tower Tunnel Telescope (KTT). For the sunspots observed in Hα wavelength region, the photospheric magnetic field is derived by inverting the Stokes profiles of Fe I line at 656.92 nm and the chromospheric magnetic field is derived under weak-field-approximation applied to the Hα Stokes profiles. For the sunspot observed in Ca II 854.2 nm wavelength region, the photospheric field is derived through inversion of Fe I line at 853.8 nm and the chromospheric magnetic field is derived through non-LTE inversion of Ca II 854.2 Stokes profiles. We will discuss in this presentation about the global magnetic properties such as radial variation of azimuthally averaged magnetic field at the photospheric and the chromospheric heights and the magnetic field gradient from photosphere to chromosphere. Further, we will briefly describe the set up at KTT for spectropolarimetric observations simultaneously in Hα and Ca II at 866.2 nm spectral lines.