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| Format: | Preprint |
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2025
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| Accès en ligne: | https://arxiv.org/abs/2510.22822 |
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| _version_ | 1866918299255701504 |
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| author | Podladchikova, Olena |
| author_facet | Podladchikova, Olena |
| contents | Solar Orbiter EUV observations reveal ubiquitous small-scale brightenings in the quiet-Sun low corona. We analyze the spatial and temporal dissipation scales of these events with a focus on the formation, evolution, and dissipation of associated current sheets. The brightenings are observed at heights of 1-5 Mm and span energies of 10^20 - 10^24 erg, well below the classical nanoflare regime, with the lowest-energy brightenings preferentially originating in the lowest coronal layers. Two distinct dissipation regimes are identified: impulsive brightenings with timescales of 1-10 s, consistent with fast, Alfvenic magnetic reconnection in low-beta plasma, and longer-lived heating episodes lasting 10-100 s, indicative of slower, resistive current-sheet dissipation under higher-beta conditions. The observed dissipation scales suggest a transition from kinetic-scale reconnection to macroscopic current-sheet heating in the low corona. These results support a multi-scale energy-release framework and highlight the role of low-altitude, small-scale current-sheet dissipation in quiet-Sun coronal heating. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_22822 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | On the Short Dissipation Scales and Current-Sheet Properties of Low-Coronal EUV Brightenings Podladchikova, Olena Solar and Stellar Astrophysics 85A30, 76X05, 62P35, 60Gxx G.1.10; I.6.4; J.2; G.3 Solar Orbiter EUV observations reveal ubiquitous small-scale brightenings in the quiet-Sun low corona. We analyze the spatial and temporal dissipation scales of these events with a focus on the formation, evolution, and dissipation of associated current sheets. The brightenings are observed at heights of 1-5 Mm and span energies of 10^20 - 10^24 erg, well below the classical nanoflare regime, with the lowest-energy brightenings preferentially originating in the lowest coronal layers. Two distinct dissipation regimes are identified: impulsive brightenings with timescales of 1-10 s, consistent with fast, Alfvenic magnetic reconnection in low-beta plasma, and longer-lived heating episodes lasting 10-100 s, indicative of slower, resistive current-sheet dissipation under higher-beta conditions. The observed dissipation scales suggest a transition from kinetic-scale reconnection to macroscopic current-sheet heating in the low corona. These results support a multi-scale energy-release framework and highlight the role of low-altitude, small-scale current-sheet dissipation in quiet-Sun coronal heating. |
| title | On the Short Dissipation Scales and Current-Sheet Properties of Low-Coronal EUV Brightenings |
| topic | Solar and Stellar Astrophysics 85A30, 76X05, 62P35, 60Gxx G.1.10; I.6.4; J.2; G.3 |
| url | https://arxiv.org/abs/2510.22822 |