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| Main Authors: | , , |
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| Format: | Preprint |
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2026
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2605.03019 |
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| _version_ | 1866917507371106304 |
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| author | Noraz, Quentin Carlsson, Mats Aulanier, Guillaume |
| author_facet | Noraz, Quentin Carlsson, Mats Aulanier, Guillaume |
| contents | Coupling between the photosphere, chromosphere and corona in the quiet Sun (QS) is governed by a complex interplay between magnetic structuring, heating, mass loading, and radiative cooling. Constraining how this balance responds to variations in small-scale magnetic flux remains limited. We investigate how chromospheric heating and its thermodynamic coupling to higher atmospheric layers vary as a function of small-scale magnetic flux emergence. We performed a parametric set of 3D radiative-MHD simulations with the Bifrost code, starting from a weakly magnetised QS reference model and injecting horizontal magnetic flux of increasing amplitude into the sub-surface convection zone. The resulting chromospheric dynamics, heating, mass loading, and coronal response were analysed. Chromospheric temperatures and mechanical heating rise monotonically with increasing magnetic-field strength. Although the fractional contribution of shocks decreases, reconnecting current sheets keeps maintaining about 50%. In contrast, the temperature at the base of the corona exhibits a non-monotonic response, reaching a maximum at intermediate magnetic amplitudes and decreasing for the strongest-field case. We show that stronger magnetic-field strength increases chromospheric heating, which increases the coronal-base density through efficient mass loading, and amplifies radiative losses. These density-driven radiative losses dominate the coronal energy balance and thus lead to reduced coronal-base temperatures despite increased heating. Our results demonstrate the sensitivity of chromospheric structure and dynamics to small-scale flux emergence, and its key role in regulating coronal thermodynamics. This result illustrates the chromosphere-s role as a thermodynamic gatekeeper, and further warrants future investigations of atmospheric models relevant to global solar-wind models and space-weather forecasts. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_03019 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Chromosphere of the quiet sun: II. Atmospheric response to small-scale magnetic flux emergence Noraz, Quentin Carlsson, Mats Aulanier, Guillaume Solar and Stellar Astrophysics Coupling between the photosphere, chromosphere and corona in the quiet Sun (QS) is governed by a complex interplay between magnetic structuring, heating, mass loading, and radiative cooling. Constraining how this balance responds to variations in small-scale magnetic flux remains limited. We investigate how chromospheric heating and its thermodynamic coupling to higher atmospheric layers vary as a function of small-scale magnetic flux emergence. We performed a parametric set of 3D radiative-MHD simulations with the Bifrost code, starting from a weakly magnetised QS reference model and injecting horizontal magnetic flux of increasing amplitude into the sub-surface convection zone. The resulting chromospheric dynamics, heating, mass loading, and coronal response were analysed. Chromospheric temperatures and mechanical heating rise monotonically with increasing magnetic-field strength. Although the fractional contribution of shocks decreases, reconnecting current sheets keeps maintaining about 50%. In contrast, the temperature at the base of the corona exhibits a non-monotonic response, reaching a maximum at intermediate magnetic amplitudes and decreasing for the strongest-field case. We show that stronger magnetic-field strength increases chromospheric heating, which increases the coronal-base density through efficient mass loading, and amplifies radiative losses. These density-driven radiative losses dominate the coronal energy balance and thus lead to reduced coronal-base temperatures despite increased heating. Our results demonstrate the sensitivity of chromospheric structure and dynamics to small-scale flux emergence, and its key role in regulating coronal thermodynamics. This result illustrates the chromosphere-s role as a thermodynamic gatekeeper, and further warrants future investigations of atmospheric models relevant to global solar-wind models and space-weather forecasts. |
| title | Chromosphere of the quiet sun: II. Atmospheric response to small-scale magnetic flux emergence |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2605.03019 |