# The 2019 July 2 Total Solar Eclipse: Prediction of the Coronal Magnetic Field Structure and Polarization Characteristics

## TL;DR

This study predicts the coronal magnetic field structure and polarization characteristics during the 2019 July 2 total solar eclipse using data-driven models, aiding future solar magnetometry observations.

## Contribution

It introduces a method combining a solar surface flux transport model with a Potential Field Source Surface model to forecast coronal magnetic structures for eclipse observations.

## Key findings

- Predicted two large-scale streamer structures on the Sun's limbs.
- Identified potential development of a pseudo-streamer based on field topology.
- Provided polarization characteristic predictions for coronal emission.

## Abstract

On 2019 July 2 a total solar eclipse -- visible across some parts of the Southern Pacific Ocean, Chile and Argentina -- will enable observations of the Sun's large-scale coronal structure. The structure of the Sun's corona and their emission characteristics are determined by underlying magnetic fields which also govern coronal heating and solar eruptive events. However, coronal magnetic field measurements remain an outstanding challenge. Computational models of coronal magnetic fields serve an important purpose in this context. Earlier work has demonstrated that the large-scale coronal field is governed by slow surface flux evolution and memory build-up which allows for prediction of the coronal structure on solar rotational timescales. Utilizing this idea and based upon a 51 day forward run of a data-driven solar surface flux transport model and a Potential Field Source Surface model, we predict the Sun's coronal structure for the 2019 July 2 solar eclipse. We also forward model the polarization characteristics of the coronal emission from the predicted magnetic fields. We predict two large-scale streamer structures and their locations on the east and west limbs of the Sun and discuss the possibility of development of a pseudo-streamer based on an analysis of field line topology. This study is relevant for coronal magnetometry initiatives from ground-based facilities such as the Daniel K. Inouye Solar Telescope and Coronal Multichannel Polarimeter, and upcoming space-based instruments such as the Solar Ultraviolet Imaging Telescope and the Variable Emission Line Coronagraph onboard ISRO's Aditya-L1 space mission.