Magnetic field evolution and topology of an AR

MANDRINI, C.H.; DENG, Y.Y.; SCHMIEDER, B.; DÉMOULIN, P.; RUDAWY, P.; NEWMARK, J.; DE FOREST, C.

Cputh

Congreso; 3rd Advances in Solar Physics Euroconferences, Magnetic Fields and Oscillations; 1998

European Solar Physics Division

Active region 7968 was observed during runs of a coordinated SOHO, Yohkoh and ground-based observatory program (Joint Observing Program, JOP, 17). The region appeared and decayed in a seven day period (June 3 to 10, 1996). In this time, mainly during June 6, it presented a very dynamical behaviour. Flux emerged in between the two main polarities and Arch Filament Systems (AFS) were observed to be linked to this emergence. We analyze the evolution of some over dark arches observed during flux emergence, forming two systems of AFS. Modelling the magnetic field, we find that these systems were associated to field lines having dips tangent to the photosphere (the so called "bald patches", BPs). We discuss their evolution in terms of emergence of the dipped portion of the lines or of magnetic field reconnection.