Turbulent transport of radiation in the solar convective zone

TL;DR

This paper investigates how turbulence in the solar convective zone enhances the effective penetration of radiation, showing that turbulence can increase radiation penetration length several times compared to classical estimates.

Contribution

It derives a mean-field equation for radiation intensity considering turbulence and demonstrates increased radiation penetration due to compressibility effects near the solar surface.

Findings

Turbulence can increase radiation penetration length by up to 2.5 times near the solar surface.

Compressibility effects significantly enhance radiation fluctuations and absorption.

Effective radiation penetration is much larger than mean penetration length in turbulent regions.

Abstract

A turbulent transport of radiation in the solar convective zone is investigated. The mean-field equation for the irradiation intensity is derived. It is shown that due to the turbulent effects, the effective penetration length of radiation can be increased in several times in comparison with the mean penetration length of radiation (defined as an inverse mean absorption coefficient). Using the model of the solar convective zone based on the mixing length theory, where the mean penetration length of radiation is usually much smaller than the turbulent correlation length, it is demonstrated that the ratio of the effective penetration length to the mean penetration length of radiation increases in 2.5 times in the vicinity of the solar surface. The main reason are the compressibility effects that become important in the vicinity of the solar surface where temperature and density fluctuations increase towards the solar surface, enhancing fluctuations of the radiation absorption coefficient and increasing the effective penetration length of radiation.