AN ANALYSIS OF PHOTOSPHERIC VECTOR MAGNETOGRAMS, H-ALPHA IMAGES AND SOFT-X-RAY IMAGES IN A SUPERACTIVE REGION NOAA-7321

Based on the photospheric vector magnetograms taken at Huairou Solar O bserving Station (HSOS), H alpha images taken at Hiraiso Solar Terrest rial Research Center of Communication Research Laboratory, soft X-ray images taken by Yohkoh and an extrapolation method, the magnetic field structures and some active phenomena of the active region AR 7321 aro und 04:12 UT on 27 October 1992 are analyzed in this paper. A divergen ce of the transverse magnetic field, located at a newly formed spot, w as found. At]east four highly sheared magnetic field systems separatel y spread from this divergence to four other sites around this divergen ce. Vertical current concentrations are upward in this region and down ward in the other four sites, and the corresponding H alpha bright pat ches and soft X-ray bright loops coincide with these structures, confi rming the existence of these four systems. The extrapolated magnetic f orce lines reconstructed by the Boundary Element Method (BEM), force-f ree field assumption, and boundary condition of observed photospheric vector magnetic field, coincide in space with the H alpha bright patch es and soft X-ray bright loops, showing that this extrapolation method is very effective and suggesting that the H alpha bright patches and soft X-ray bright loops in this case represent the magnetic field stru ctures in the upper atmosphere of the Sun. The bright structures in th e H alpha images and the soft X-ray images have a close correlation wi th the non-potential characteristics of the magnetic fields.