Sunspot umbra atmosphere from full Stokes inversion

TL;DR

This study uses full Stokes spectropolarimetric inversion to analyze the sunspot umbra atmosphere, revealing the vertical structure of temperature and magnetic fields, enhancing understanding of sunspot physics and solar magnetic field generation.

Contribution

It introduces a novel combined analysis of atomic and molecular lines in spectropolarimetric data to improve sunspot umbra modeling.

Findings

Detailed height-dependent profiles of temperature and magnetic field in sunspot umbra.

Enhanced sunspot models incorporating molecular line data.

Insights into energy transport within sunspots.

Abstract

Sunspots are prominent manifestations of the solar cycle and provide key constraints for understanding its operation. Also, knowing internal structure of sunspots allows us to gain insights on the energy transport in strong magnetic fields and, thus, on the processes inside the convection zone, where solar magnetic fields are generated and amplified before emerging at the surface on various scales, even during solar minima. In this paper, we present results of a spectropolarimetric analysis of a sunspot observed during the declining phase of the solar cycle 23. By inversion of full Stokes spectra observed in several spectral regions in the optical at the THEMIS facility we infer the height dependence of physical quantities such as the temperature and the magnetic field strength for different sunspot regions. The simultaneous use of atomic (Fe{\sc i} 5250.2 and 5250.6 \AA) and highly temperature sensitive molecular (TiO 7055 \AA and MgH 5200 \AA) lines allow us to improve a model of the sunspot umbra.