caa a22 4500 445346604 CHVBK 20180317142830.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s11207-010-9670-9 doi (NATIONALLICENCE)springer-10.1007/s11207-010-9670-9 Homologous Flares and Magnetic Field Topology inActive Region NOAA 10501 on 20 November 2003 [Elektronische Daten] [R. Chandra, B. Schmieder, C. Mandrini, P. Démoulin, E. Pariat, T. Török, W. Uddin] We present and interpret observations of two morphologically homologous flares that occurred in active region (AR) NOAA 10501 on 20 November 2003. Both flares displayed four homologous Hα ribbons and were both accompanied by coronal mass ejections (CMEs). The central flare ribbons were located at the site of an emerging bipole in the centre of the active region. The negative polarity of this bipole fragmented in two main pieces, one rotating around the positive polarity by ≈ 110° within 32 hours. We model the coronal magnetic field and compute its topology, using as boundary condition the magnetogram closest in time to each flare. In particular, we calculate the location of quasi-separatrix layers (QSLs) in order to understand the connectivity between the flare ribbons. Though several polarities were present in AR 10501, the global magnetic field topology corresponds to a quadrupolar magnetic field distribution without magnetic null points. For both flares, the photospheric traces of QSLs are similar and match well the locations of the four Hα ribbons. This globally unchanged topology and the continuous shearing by the rotating bipole are two key factors responsible for the flare homology. However, our analyses also indicate that different magnetic connectivity domains of the quadrupolar configuration become unstable during each flare, so that magnetic reconnection proceeds differently in both events. Springer Science+Business Media B.V., 2010 Active regions, magnetic fields nationallicence Flares, dynamics nationallicence Flares, relation to magnetic field nationallicence Chandra R. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut Schmieder B. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut Mandrini C. Instituto de Astronomía y Física del Espacio (IAFE), CONICET-UBA, Buenos Aires, Argentina aut Démoulin P. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut Pariat E. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut Török T. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut Uddin W. Aryabhatta Research Institute of Observational Sciences (ARIES), 263 129, Nainital, India aut Solar Physics Springer Netherlands 269/1(2011-03-01), 83-104 0038-0938 269:1<83 2011 269 11207 https://doi.org/10.1007/s11207-010-9670-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-010-9670-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chandra R. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut NATIONALLICENCE 700 1- Schmieder B. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut NATIONALLICENCE 700 1- Mandrini C. Instituto de Astronomía y Física del Espacio (IAFE), CONICET-UBA, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- Démoulin P. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut NATIONALLICENCE 700 1- Pariat E. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut NATIONALLICENCE 700 1- Török T. Observatoire de Paris, LESIA, UMR8109 (CNRS), 92195, Meudon Principal Cedex, France aut NATIONALLICENCE 700 1- Uddin W. Aryabhatta Research Institute of Observational Sciences (ARIES), 263 129, Nainital, India aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 269/1(2011-03-01), 83-104 0038-0938 269:1<83 2011 269 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer