Bright points and subflares in ultraviolet lines and X-rays
We have analyzed an active region which was observed in Hα (Multichannel Subtractive Double Pass Spectrograph), in UV lines (SMM/UVSP), and in X-rays (SMM/HXIS). In this active region there were only a few subflares and many small bright points visible in UV and in X-rays. Using an extrapolation bas...
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todo:paper_0004637X_v510_n1PART1_p474_Rovira2023-10-03T14:01:45Z Bright points and subflares in ultraviolet lines and X-rays Rovira, M. Schmieder, B. Démoulin, P. Simnett, G.M. Hagyard, M.J. Reichmann, E. Tandberg-Hanssen, E. Sun: flares Sun: UV radiation Sun: X-rays, gamma rays We have analyzed an active region which was observed in Hα (Multichannel Subtractive Double Pass Spectrograph), in UV lines (SMM/UVSP), and in X-rays (SMM/HXIS). In this active region there were only a few subflares and many small bright points visible in UV and in X-rays. Using an extrapolation based on the Fourier transform, we have computed magnetic field lines connecting different photospheric magnetic polarities from ground-based magnetograms. Along the magnetic inversion lines we find two different zones: (1) a high-shear region (>70°) where subflares occur, and (2) a low-shear region along the magnetic inversion line where UV bright points are observed. In these latter regions the magnetic topology is complex with a mixture of polarities. According to the velocity field observed in the Si IV λ1402 line and the extrapolation of the magnetic field, we notice that each UV bright point is consistent with emission from low-rising loops with downflows at both ends. We notice some hard X-ray emissions above the bright-point regions with temperatures up to 8 × 106 K, which suggests some induced reconnection due to continuous emergence of new flux. This reconnection is also enhanced by neighboring subflares. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0004637X_v510_n1PART1_p474_Rovira |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Sun: flares Sun: UV radiation Sun: X-rays, gamma rays |
| spellingShingle |
Sun: flares Sun: UV radiation Sun: X-rays, gamma rays Rovira, M. Schmieder, B. Démoulin, P. Simnett, G.M. Hagyard, M.J. Reichmann, E. Tandberg-Hanssen, E. Bright points and subflares in ultraviolet lines and X-rays |
| topic_facet |
Sun: flares Sun: UV radiation Sun: X-rays, gamma rays |
| description |
We have analyzed an active region which was observed in Hα (Multichannel Subtractive Double Pass Spectrograph), in UV lines (SMM/UVSP), and in X-rays (SMM/HXIS). In this active region there were only a few subflares and many small bright points visible in UV and in X-rays. Using an extrapolation based on the Fourier transform, we have computed magnetic field lines connecting different photospheric magnetic polarities from ground-based magnetograms. Along the magnetic inversion lines we find two different zones: (1) a high-shear region (>70°) where subflares occur, and (2) a low-shear region along the magnetic inversion line where UV bright points are observed. In these latter regions the magnetic topology is complex with a mixture of polarities. According to the velocity field observed in the Si IV λ1402 line and the extrapolation of the magnetic field, we notice that each UV bright point is consistent with emission from low-rising loops with downflows at both ends. We notice some hard X-ray emissions above the bright-point regions with temperatures up to 8 × 106 K, which suggests some induced reconnection due to continuous emergence of new flux. This reconnection is also enhanced by neighboring subflares. |
| format |
JOUR |
| author |
Rovira, M. Schmieder, B. Démoulin, P. Simnett, G.M. Hagyard, M.J. Reichmann, E. Tandberg-Hanssen, E. |
| author_facet |
Rovira, M. Schmieder, B. Démoulin, P. Simnett, G.M. Hagyard, M.J. Reichmann, E. Tandberg-Hanssen, E. |
| author_sort |
Rovira, M. |
| title |
Bright points and subflares in ultraviolet lines and X-rays |
| title_short |
Bright points and subflares in ultraviolet lines and X-rays |
| title_full |
Bright points and subflares in ultraviolet lines and X-rays |
| title_fullStr |
Bright points and subflares in ultraviolet lines and X-rays |
| title_full_unstemmed |
Bright points and subflares in ultraviolet lines and X-rays |
| title_sort |
bright points and subflares in ultraviolet lines and x-rays |
| url |
http://hdl.handle.net/20.500.12110/paper_0004637X_v510_n1PART1_p474_Rovira |
| work_keys_str_mv |
AT roviram brightpointsandsubflaresinultravioletlinesandxrays AT schmiederb brightpointsandsubflaresinultravioletlinesandxrays AT demoulinp brightpointsandsubflaresinultravioletlinesandxrays AT simnettgm brightpointsandsubflaresinultravioletlinesandxrays AT hagyardmj brightpointsandsubflaresinultravioletlinesandxrays AT reichmanne brightpointsandsubflaresinultravioletlinesandxrays AT tandberghanssene brightpointsandsubflaresinultravioletlinesandxrays |
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1807317392908353536 |