Influence of numerical domain design in simulations of solar coronal heating with the MAGEC code
Year: 2026
Type: article
Abstract: Context. Numerical simulations are essential for studying the complex structure of the solar atmosphere, especially in the context of the coronal heating problem. Understanding how numerical factors and boundary conditions (BCs) influence the energetic structure of these models is crucial for unraveling the mechanisms behind the heating of the solar corona. Aims. We investigate how the spatial dimensions of the computational domain, the upper BCs, and the vertical grid resolution influence the relaxed thermal structure, energetics, and long-term stability of simulations of the solar atmosphere in 2D with a vertical magnetic field. Methods. Using the MAGEC code, we conducted several 2D parametric studies, varying the domain width and height, vertical grid stretching, and top BCs (including the hot-plate, closed, unrestricted temperature, background heating configurations, and nonreflecting characteristics). We evaluated the resulting average temperature profiles to determine their parameter dependence and temporal stability. Additionally, we analyzed the accumulated energetic budget as a function of height, isolating the contributions from radiative losses, thermal conduction, pressure work, and internal energy flux; this allowed us to evaluate how the balance of these distinct energetic contributions shifts depending on the chosen top BCs and explain the relaxed thermal profiles of the models. Results. The temperature structure of the models behaves significantly differently as a function of the domain height and top BC. We identified clear dependencies of these factors on the average temperature profile and the gradient of the horizontally averaged transition region (TR). In general, models with larger vertical domains yield higher average temperatures in the intermediate corona and steeper gradients across the average TR. Comparative analysis reveals that, among the less artificial BCs, the nonreflecting characteristics are the most effective at delaying coronal cooling. Furthermore, we determined the threshold height at which simulations that employ a dynamic top BC can effectively mimic the temporal behavior of fixed-temperature setups. We also established the maximum allowable degree of grid stretching in the corona that preserves physical accuracy while substantially reducing computational costs. Finally, the accumulated effects of the energetic terms change significantly according to the chosen BC, with specific mechanisms acting as cooling agents in different layers of the atmosphere. Conclusions. Our results demonstrate that in 2D the domain height, vertical grid design, and BC critically dictate the relaxed thermal structure and energetic balance of the simulated solar atmosphere.
Source: Astronomy and Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Awards: G1105844351, G2257393230, G3007883777, G318412399, G3273706125, G410571670, G451917667, G491712853, G4993905653, G5195188938, G523076202, G5539308778, G5635532810, G593054264, G5967599077, G6033112984, G6218905885, G6520718613, G7127239378, G717256432, G7395345766, G7695848745, G7805626310, G7863371703, G7935329467, G8096386515, G833286518, G8497050386, G8667377315, G8699118962, G8864841362, G8888022036, G9000451760
OpenAlex ID: W7222760055