Coronal temperature profiles obtained from kinetic models and from coronal brightness measurements obtained during solar eclipses

TL;DR

This study compares coronal temperature and heat flux profiles derived from kinetic models and white light observations during solar eclipses, revealing similarities at large distances but differences near the Sun, suggesting extended heating sources.

Contribution

It provides a comparative analysis of coronal profiles from kinetic models and observational data, highlighting discrepancies close to the Sun and implications for coronal heating.

Findings

Similar temperature and density distributions at >7 Rs in both models.

Differences in heat flux directions near the Sun, indicating extended heating sources.

Heat flux from observations opposes that from the kinetic model near the Sun.

Abstract

Coronal density, temperature and heat flux distributions for the equatorial and polar corona have been deduced by Lemaire [2012] from Saito's model of averaged coronal white light (WL) brightness and polarization observations. They are compared with those determined from a kinetic collisionless/exospheric model of the solar corona. This comparison indicates rather similar distributions at large radial distances (> 7 Rs) in the collisionless region. However, rather important differences are found close to the Sun in the acceleration region of the solar wind. The exospheric heat flux is directed away from the Sun, while that inferred from all WL coronal observations is in the opposite direction, i.e., conducting heat from the inner corona toward the chromosphere. This could indicate that the source of coronal heating rate extends up into the inner corona where it maximizes at r > 1.5 Rs well above the transition region.