Structure of the solar photosphere studied from the radiation hydrodynamics code ANTARES

TL;DR

This paper introduces the ANTARES radiation hydrodynamics code for detailed solar photosphere modeling, demonstrating its capability to simulate solar granulation and stratification, and providing new insights into the structure and dynamics of the quiet Sun.

Contribution

The paper presents a state-of-the-art numerical tool, ANTARES, capable of high-resolution solar granulation simulations and detailed analysis of photospheric stratification, advancing solar physics modeling capabilities.

Findings

The thermal convection zone extends about ten kilometers above the solar surface.

Convective overshooting gas penetrates into the low photosphere.

A transition layer of approximately 145 km separates convective and oscillatory layers.

Abstract

The ANTARES radiation hydrodynamics code is capable of simulating the solar granulation in detail unequaled by direct observation. We introduce a state-of-the-art numerical tool to the solar physics community and demonstrate its applicability to model the solar granulation. The code is based on the weighted essentially non-oscillatory finite volume method and by its implementation of local mesh refinement is also capable of simulating turbulent fluids. While the ANTARES code already provides promising insights into small-scale dynamical processes occurring in the quiet-Sun photosphere, it will soon be capable of modeling the latter in the scope of radiation magnetohydrodynamics. In this first preliminary study we focus on the vertical photospheric stratification by examining a 3-D model photosphere with an evolution time much larger than the dynamical timescales of the solar granulation and of particular large horizontal extent corresponding to $25\!" \!\! \times \, 25\!"$ on the solar surface to smooth out horizontal spatial inhomogeneities separately for up- and downflows. The highly resolved Cartesian grid thereby covers $\sim 4~\mathrm{Mm}$ of the upper convection zone and the adjacent photosphere. Correlation analysis, both local and two-point, provides a suitable means to probe the photospheric structure and thereby to identify several layers of characteristic dynamics: The thermal convection zone is found to reach some ten kilometers above the solar surface, while convectively overshooting gas penetrates even higher into the low photosphere. An $\approx 145\,\mathrm{km}$ wide transition layer separates the convective from the oscillatory layers in the higher photosphere.