Executive Summary : | The Sun's solar atmosphere is heated to millions of kelvins due to magnetic activity on all scales. The Zeeman effect and the Hanle effect are used to diagnose strong and weak magnetic fields in the solar atmosphere. The Hanle effect in Ca I 4227 A line is a good choice for inferring weak magnetic fields in the lower Solar atmosphere due to its largest degree of observed resonance scattering polarization. Anusha et al. (2011a) modeled the linear polarization observations of the Ca I 4227 A line near the disk center in a weakly magnetized region using one-dimensional (1d) model solar atmospheres. However, the limb polarization of the Ca I 4227 A line is not yet fully understood. The reasons for discrepancies include partial frequency redistribution (PFR), spatial gradients in the bulk velocity of the gas, and 1d atmospheric models. The intricate nonlinear coupling between frequencies, angles, and spatial domain makes it computationally demanding. With the high resolving power of the world's largest solar telescope Daniel K. Inouye Solar Telescope (DKIST) becoming operational and India's National Large Solar Telescope (NLST), it is time to increase the realism in modeling efforts to match with high-quality data. The proposed project aims to develop a tool to model the Ca I 4227 A line that solves polarized radiative transfer equation with velocity and magnetic field-induced angle-dependent PFR on 3d model solar atmospheres having realistic velocity and magnetic fields. Successful modeling of the Ca I 4227 A line also intends to complement chromospheric studies in other strong spectral lines, such as Ca II and Mg II h and k, to be observed through Adithya-L1, India's first space mission to the Sun. |