Abstract Details

Name: Alok Ranjan Tiwary
Affiliation: Jai Prakash University, Chapra
Conference ID: ASI2020_499
Title : Measurement of Solar Magnetic Fields: Development of a Polarimeter for Multi-Application Solar Telescope
Authors and Co-Authors : Dr. Alok Ranjan Tiwary
Abstract Type : Oral
Abstract Category : Thesis
Abstract : The focus of my thesis work is based on the development of a polarimeter for measuring the polarization signal induced in the photosphere and chromospheres. The main component of the polarimeter is Liquid Crystal Variable Retarders (LCVRs). It is well known that the characterization and calibration of LCVRs is very important in order to get the required polarimetric accuracy for the polarization measurements. In my thesis work I have characterized two set of LCVRs of two different polarimeter for Multi Application Solar Telescope at Udaipur Solar Observatory, India, designed for photospheric and Chromospheric magnetic field measurements. I have also calibrated these two polarimeter using calibration units. In the thesis, spectropolarimetric observations of various active regions obtained with the imaging spectropolarimeter for MAST are also presented. For verification, we have made comparison of line-of-sight observations of a selected active region obtained from the Helioseismic Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) with that obtained from observartions in the spectral line 6173 \AA from MAST telescope. We found good agreement between both the line-of-sight observations, considering the fact that MAST observations are limited by atmospheric seeing.