Magnetic configuration reorganisation before the X 17 flare of October28 2003

SCHMIEDER, B.; MANDRINI, C.H.; DÉMOULIN, P.; PARIAT, E.; BERLICKI, A.; DELUCA, E.E.

París

Congreso; 35th COSPAR Scientific Assembly; 2004

IAU

The active region NOAA 0486 was observed during a multi-wavelength campaign with ground based and space instruments. We analyse the magnetic configuration of the region during a pre-event, which reorganizes the magnetic connectivities of the field lines before the occurence of a X17 flare of October 28 2003. The magnetic field was observed with THEMIS and MDI, the chromosphere with the MSDP operating on on THEMIS and with the Meudon heliograph, the EUV images with SOHO/CDS and TRACE. The X17 flare gave a halo CME while the M1.9 flare has no corresponding CME. The magnetic field analysis of the active regions is performed by using a linear-force-free field code. The pre-flare event before the X17 flare changes the connectivities in a first phase and allows the stressed field to relax in a second phase producing the X17 flare.