ARCH FILAMENT SYSTEMS ASSOCIATED WITH X-RAY LOOPS

Using multi-wavelength observations obtained with the Tenerife telesco pes (VTT and GCT) and with the Yohkoh satellite, we observed new emerg ing flux with an associated arch filament system (AFS) in the chromosp here and bright X-ray loops in the corona. We observed the change of c onnectivity of the X-ray loop footpoints which may be at the origin of the occurrence of a subflare. Densities, gas and magnetic pressures o f cold AFS and hot loops were derived and discussed. The extrapolation of the photospheric magnetic field observed with the GCT in a linear force-free field assumption (constant alpha) shows that this region, i n spite of having roughly a global potential configuration, consists o f two systems of arch filaments. We found these two systems best fitte d with two sheared magnetic topologies of opposite alpha values of +/- 0.1 Mm(-1).