HR: 1330h
AN: SH22A-0174    [PDF]
TI: The Active Region 8210: Observations, Coronal Magnetic Fields and Energetics
AU: * Regnier, S
EM: regnier@mithra.physics.montana.edu
AF: Montana State University, Physics Department 264 EPS Building POB 173840, Bozeman, MT 59717 United States
AU: Canfield, R C
EM: canfield@solar.physics.montana.edu
AF: Montana State University, Physics Department 264 EPS Building POB 173840, Bozeman, MT 59717 United States
AB: The active region 8210 observed on May 1, 1998 is the site of several flares (3 C-class flares from 17:00 UT to 22:00 UT and one M-class flare at 22:40 UT). In this study, we analyse the causes and consequences of these flares inside the coronal magnetic configurations: sunspot rotation, moving features, cancellation of flux. The time evolution of AR 8210 from observations (magnetograms, H$\alpha$, EUV, Soft X-rays) and the nonlinear force-free reconstructed magnetic fields reveals that the sites of activity are related to the topological skeleton (null points, separatrix surfaces, separators): field lines crossing a separatrix surface reconnect in an other connectivity domain and produce an H$\alpha$ brightening at the footpoints. We also determine the free magnetic energy budget (difference between nonlinear and potential field magnetic energy) and the relative magnetic helicity. The photospheric increase (or decrease) of magnetic flux is related to the evolution of the magnetic energy in the corona above the active region as well as to the occurence of flares. The main photospheric changes occur between the times of flaring activity. AR 8210 is a case study for the Solar MURI project.
DE: 7509 Corona
DE: 7519 Flares
DE: 7524 Magnetic fields
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting