What is the role of magnetic null points in large flares?
We have performed the analysis of the magnetic topology of active region NOAA 10486 before two large flares occurring on October 26 and 28, 2003. The 3D extrapolation of the photospheric magnetic field shows the existence of magnetic null points when using two different methods. We use TRACE 1600 Å...
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2007
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02731177_v39_n12_p1840_Schmieder http://hdl.handle.net/20.500.12110/paper_02731177_v39_n12_p1840_Schmieder |
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paper:paper_02731177_v39_n12_p1840_Schmieder2023-06-08T15:25:35Z What is the role of magnetic null points in large flares? flares magnetic fields Magnetic reconnection Sun X-rays 3D extrapolation Magnetic null points Magnetic topology Quasi-separatrix layers Magnetic fields Space research X rays Topology We have performed the analysis of the magnetic topology of active region NOAA 10486 before two large flares occurring on October 26 and 28, 2003. The 3D extrapolation of the photospheric magnetic field shows the existence of magnetic null points when using two different methods. We use TRACE 1600 Å and 195 Å brightenings as tracers of the energy release due to magnetic reconnections. We conclude on the three following points:1.The small events observed before the flares are related to low lying null points. They are long lasting and associated with low energy release. They are not triggering the large flares.2.On October 26, a high altitude null point is found. We look for bright patches that could correspond to the signatures of coronal reconnection at the null point in TRACE 1600 Å images. However, such bright patches are not observed before the main flare, they are only observed after it.3.On October 28, four ribbons are observed in TRACE images before the X17 flare. We interpret them as due to a magnetic breakout reconnection in a quadrupolar configuration. There is no magnetic null point related to these four ribbons, and this reconnection rather occurs at quasi-separatrix layers (QSLs). We conclude that the existence of a null point in the corona is neither a sufficient nor a necessary condition to give rise to large flares. © 2007 COSPAR. 2007 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02731177_v39_n12_p1840_Schmieder http://hdl.handle.net/20.500.12110/paper_02731177_v39_n12_p1840_Schmieder |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
flares magnetic fields Magnetic reconnection Sun X-rays 3D extrapolation Magnetic null points Magnetic topology Quasi-separatrix layers Magnetic fields Space research X rays Topology |
| spellingShingle |
flares magnetic fields Magnetic reconnection Sun X-rays 3D extrapolation Magnetic null points Magnetic topology Quasi-separatrix layers Magnetic fields Space research X rays Topology What is the role of magnetic null points in large flares? |
| topic_facet |
flares magnetic fields Magnetic reconnection Sun X-rays 3D extrapolation Magnetic null points Magnetic topology Quasi-separatrix layers Magnetic fields Space research X rays Topology |
| description |
We have performed the analysis of the magnetic topology of active region NOAA 10486 before two large flares occurring on October 26 and 28, 2003. The 3D extrapolation of the photospheric magnetic field shows the existence of magnetic null points when using two different methods. We use TRACE 1600 Å and 195 Å brightenings as tracers of the energy release due to magnetic reconnections. We conclude on the three following points:1.The small events observed before the flares are related to low lying null points. They are long lasting and associated with low energy release. They are not triggering the large flares.2.On October 26, a high altitude null point is found. We look for bright patches that could correspond to the signatures of coronal reconnection at the null point in TRACE 1600 Å images. However, such bright patches are not observed before the main flare, they are only observed after it.3.On October 28, four ribbons are observed in TRACE images before the X17 flare. We interpret them as due to a magnetic breakout reconnection in a quadrupolar configuration. There is no magnetic null point related to these four ribbons, and this reconnection rather occurs at quasi-separatrix layers (QSLs). We conclude that the existence of a null point in the corona is neither a sufficient nor a necessary condition to give rise to large flares. © 2007 COSPAR. |
| title |
What is the role of magnetic null points in large flares? |
| title_short |
What is the role of magnetic null points in large flares? |
| title_full |
What is the role of magnetic null points in large flares? |
| title_fullStr |
What is the role of magnetic null points in large flares? |
| title_full_unstemmed |
What is the role of magnetic null points in large flares? |
| title_sort |
what is the role of magnetic null points in large flares? |
| publishDate |
2007 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02731177_v39_n12_p1840_Schmieder http://hdl.handle.net/20.500.12110/paper_02731177_v39_n12_p1840_Schmieder |
| _version_ |
1768545830940180480 |