HR: 0830h
AN: SH51C-09    [Abstracts]
TI: Energetics of AR 0486 from line-of-sight and vector magnetograms
AU: * Regnier, S
EM: sregnier@rssd.esa.int
AF: ESA Research and Scientific Support Department, ESTEC, Keplerlaan 1, Noordwijk, 2201 AZ Netherlands
AU: Fleck, B
EM: bfleck@esa.nascom.nasa.gov
AF: ESA Research and Scientific Support Department, ESTEC, Keplerlaan 1, Noordwijk, 2201 AZ Netherlands
AB: Over two weeks in October/November 2003, the Sun featured unusually strong activity, with three large sunspot groups (including the largest one of this solar cycle), twelve X-class flares (including the strongest ever recorded), numerous halo coronal mass ejections (two with near-recorded speeds) and two significant proton storms. Eight of the twelve X-class flares originated from active region AR 10486. To understand the reasons of this peculiar activity, we investigate the evolution of the coronal magnetic field configuration as well as the energetics of AR 10486 before and after the X17.2 flare on October 28. To determine the coronal magnetic fields, we use potential and nonlinear force-free reconstruction techniques using line-of-sight (SOHO/MDI) and vector (MSO/IVM, Huairou, BBSO) magnetograms on the photosphere as boundary conditions. We identify the source region of the flare as related to the existence of null point or separator field line evidenced in a reversed-Y magnetic configuration. From the 3D configurations we derive the magnetic energy budget which can be released during the impulsive phase of the flare. The estimated free magnetic energy is enough to trigger an X-class flare. The continuous evolution of the magnetic energy derived from the potential field extrapolations indicates that the flare does not modify the distribution of magnetic field on the photosphere. We also study the distribution of energy before and after the flare using different vector magnetic field measurements.
DE: 7509 Corona
DE: 7513 Coronal mass ejections
DE: 7519 Flares
DE: 7524 Magnetic fields
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2005 Joint Assembly