Advances and Challenges in Observations and Modeling of the Global-Sun Dynamics and Dynamo

TL;DR

This paper reviews advances and challenges in understanding the Sun's internal dynamics and magnetic field generation through computational models, highlighting the limitations of current simulations and the potential of mean-field approaches.

Contribution

It provides a comprehensive overview of the current state of solar dynamo modeling, emphasizing the need for integrating 3D MHD simulations with mean-field methods.

Findings

Current 3D MHD simulations cannot fully reproduce helioseismic and surface observations.

Mean-field models can replicate many solar features but lack detailed physics of large-scale convection.

Synergizing different modeling approaches is crucial for future progress.

Abstract

Computational heliophysics has shed light on the fundamental physical processes inside the Sun, such as the differential rotation, meridional circulation, and dynamo-generation of magnetic fields. However, despite the substantial advances, the current results of 3D MHD simulations are still far from reproducing helioseismic inferences and surface observations. The reason is the multi-scale nature of the solar dynamics, covering a vast range of scales, which cannot be solved with the current computational resources. In such a situation, significant progress has been achieved by the mean-field approach, based on the separation of small-scale turbulence and large-scale dynamics. The mean-field simulations can reproduce solar observations, qualitatively and quantitatively, and uncover new phenomena. However, they do not reveal the complex physics of large-scale convection, solar magnetic cycles, and the magnetic self-organization that causes sunspots and solar eruptions. Thus, developing a synergy of these approaches seems to be a necessary but very challenging task.