MULTIWAVELENGTH OBSERVATIONS OF POST-FLARE LOOPS IN 2 LONG-DURATION SOLAR-FLARES

We have analysed two Long Duration solar Events (LDEs) which produced large systems of Post Flare Loops (PFLs) and which have been observed by Yohkoh and groundbased observatories. Using the Maximum Entropy Met hod (MEM) image synthesis technique with new modulation patterns we we re able to make hard X-ray (HXR) images of the post flare loops record ed in the L Channel (13.9-22.7 keV) of the Yohkoh Hard X-ray Telescope . We obtained co-aligned 2-D maps in H alpha (10(4) K), in soft X-rays (5 x 10(6) K) and in hard Xrays (20 x 10(6) K). We conclude that the soft X-ray (SXR) loops lie higher than the H alpha loops and the forme r are overlaid by HXR emission. This is suggestive of the magnetic rec onnection process. However some details are not consistent with the st andard models. Firstly the separation between the HXR source and the S XR loop increases with time, with the HXR source being approximately a factor of five larger than the equivalent source in impulsive flares. Secondly the cooling times deduced from observations are longer than the theoretically expected ones and the discrepancy increases with tim e. We review the current models in view of these results.