Convective Magnetic Flux Emergence Simulations from the Deep Solar Interior to the Photosphere: Comprehensive Study of Flux Tube Twist
Year: 2024
Type: article
Abstract: The emergence of magnetic flux from the deep convection zone plays an important role in solar magnetism, such as the generation of active regions and triggering of various eruptive phenomena, including jets, flares, and coronal mass ejections. To investigate the effects of magnetic twist on flux emergence, we performed numerical simulations of flux tube emergence using the radiative magnetohydrodynamic code R2D2 and conducted a systematic survey on the initial twist. Specifically, we varied the twist of the initial tube both positively and negatively from zero to twice the critical value for kink instability. As a result, regardless of the initial twist, the flux tube was lifted by the convective upflow and reached the photosphere to create sunspots. However, when the twist was too weak, the photospheric flux was quickly diffused and not retained long as coherent sunspots. The degree of magnetic twist measured in the photosphere conserved the original twist relatively well and was comparable to actual solar observations. Even in the untwisted case, a finite amount of magnetic helicity was injected into the upper atmosphere because the background turbulence added helicity. However, when the initial twist exceeded the critical value for kink instability, the magnetic helicity normalized by the total magnetic flux was found to be unreasonably larger than the observations, indicating that the kink instability of the emerging flux tube may not be a likely scenario for the formation of flare-productive active regions.
Source: The Astrophysical Journal
Authors: Shin Toriumi, Hideyuki Hotta, Kanya Kusano
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Awards: G1498581446, G1875987778, 大規模数値計算を用いた太陽11年周期の物理機構の解明, Advancing Solar Dynamo Research through Ultra-High-Precision Analyses of Carbon-14, Challenge for convective conundrum with large-scale numerical simulations, New Physical Picture of Plasma Heating Revealed by Advanced Large Solar Telescope DKIST, G6387438658, Theoretical studies on evolution of stellar coronae, Understanding and realization of advanced prediction for solar explosions with the integrated model including from stellar convection zone to interplanetary space
OpenAlex ID: W4404068061