Flare loop geometry

In selected flares that occurred in AR 7260, we have studied the geometry o f the brightest soft X-ray loop by tracing it on an image. Even under the a ssumption that the loop is contained in a plane, it is clear that a single image does not permit us to determine the full geometry. It only provides p ossible loop shapes as a function of the inclination angle of the loop plan e with respect to the vertical. However, all the loops that reproduce the o bserved appearance give the same direction of increasing height as projecte d on to the image plane. This direction is compared with two relevant obser vations. Based on 2-D reconnection models that involve a cusp configuration , it is expected that the soft X-ray loop top source moves upward with time and that a higher temperature region exists above the loop top. Several fl ares are found to contradict these predictions, presumably implying the ina dequacy of the models. Lastly we discuss a possibility of constraining the inclination angle (and hence the loop shape) with spatially-unresolved soft X-ray line spectra which are Doppler-shifted due to plasma upflows.