| Issue |
EAS Publications Series
Volume 55, 2012
4th French-Chinese Meeting on Solar Physics - Understanding Solar Activity: Advances and Challenges
|
|
|---|---|---|
| Page(s) | 143 - 145 | |
| Section | Active Regions | |
| DOI | https://doi.org/10.1051/eas/1255020 | |
| Published online | 27 June 2012 | |
M. Faurobert, C. Fang and T. Corbard (eds)
EAS Publications Series, 55 (2012) 143-145
Electric current density and related sigmoid in an active region
1
Institut d’Astrophysique Spatiale, CNRS-UMR 8617, Université
Paris-Sud 11, 91405
Orsay Cedex,
France
2
Observatoire de Paris, LESIA, CNRS-INSU-UMR 8109, UPMC Univ. Paris
06, Université Paris Diderot, Paris
7, 5 place Jules Janssen, 92190
Meudon,
France
Using THEMIS vector magnetograms we measured vertical electric current density in the leading sunspot of NOAA 11127 active region during its disk passage. The current structures evolve versus time. MHD modelling allows us to explain the spiral pattern by torsion. We found observational visible counterparts in the SDO/AIA 335 A images. The field lines are visible as loops in the AIA images. When the torsion is increasing, a sigmoid is observed. In the present event observed on November 24th 2010, we find that reconnection is also necessary to explain their sigmoidal shape.
© EAS, EDP Sciences 2012