Inversion of Zeeman polarization for solar magnetic field diagnostics

TL;DR

This paper introduces a new inversion technique and numerical code for solar magnetic field diagnostics using Zeeman polarization, demonstrating promising accuracy and application to real and synthetic data.

Contribution

The paper presents a novel inversion method and code that efficiently interprets Stokes profiles to determine magnetic fields as a function of line formation height.

Findings

The code accurately recovers input magnetic fields in synthetic tests.

Performance is comparable to existing codes like HAO MERLIN.

Application to real data shows practical utility.

Abstract

The topic of magnetic field diagnostics with the Zeeman effect is currently vividly discussed. There are some testable inversion codes available to the spectropolarimetry community and their application allowed for a better understanding of the magnetism of the solar atmosphere. In this context, we propose an inversion technique associated with a new numerical code. The inversion procedure is promising and particularly successful for interpreting the Stokes profiles in quick and sufficiently precise way. In our inversion, we fit a part of each Stokes profile around a target wavelength, and then determine the magnetic field as a function of the wavelength which is equivalent to get the magnetic field as a function of the height of line formation. To test the performance of the new numerical code, we employed "hare and hound" approach by comparing an exact solution (called input) with the solution obtained by the code (called output). The precision of the code is also checked by comparing our results to the ones obtained with the HAO MERLIN code. The inversion code has been applied to synthetic Stokes profiles of the Na D$_{1}$ line available in the literature. We investigated the limitations in recovering the input field in case of noisy data. As an application, we applied our inversion code to the polarization profiles of the Fe {\sc i} $\lambda$ 6302.5 \AA\ observed at IRSOL in Locarno.