Emerging flux as seen by Yohkoh

VAN DRIEL-GESZRELYI, L.; SCHMIEDER, B.; DÉMOULIN, P.; MANDRINI, C. H.; CAUZZI, G.; HOFMANN, A.; NITTA, N.; KUROKAWA, H.; MEIN, N.; MEIN, P.

Benesov

Workshop; JOSO Annual Meeting; 1995

Ground-based optical observations coordinated with Yohkoh/SXT X-ray observations of an old, disintegrating bipolar active region AR NOAA 7493 (May 1, 1993) provided a multiwavelength data base to study a flaring `active region' X-ray bright point (XBP) of about 16 hr lifetime, and the activity related to it in different layers of the solar atmosphere. The XBP appeared to be related to a new minor bipole. Superposed on a global evolution of soft X-ray brightness, the XBP displayed changes of brightness. During the brightenings the XBP apparently had a spatial structure, which was (tiny) loop-like rather than point-like. The X-ray brightenings were correlated with chromospheric activity. We propose that the XBP brightenings were due to reconnection of the magnetic field lines between the new bipole and a pre-existing plage field induced by the motion of one of the new pores.