Previous
abstract 
Next
abstract
We studied the wealth of structural features visible in Yohkoh/SXT and NSO/KP synoptic maps of the Sun that cover Carrington rotations 1847 through 1879. In order to do this comparison, various methods to reduce soft X-ray maps to simple structural elements were explored. In the end, the best way of comparing the various data sets turned out to be to filter the X-ray maps to emphasize high-spatial frequencies and then to either simply blink the various images or to make colorized composite maps that distinctively assign different colors to various quantities. Among the results are: 1. Active regions exhibit normal or "anemone" (fountain-like) X-ray loop structure tendency depending on whether the surrounding large-scale unipolarity of the magnetic field is small or large. 2. There is a systematic twist of the coronal loops around magnetic concentrations in the southern hemisphere and vice-versa in the north. The sense is the same as one would expect from the action of differential rotation. 3. Dark lanes in the X-ray images are centered over large-scale polarity patterns of one sign or the other. 4. The X-ray loops at the boundaries between large-scale opposite polarity patterns are frequently strongly sheared. The presence or absence of a filament in these locations may be related in a complicated way to the amount of shear. 5. At the resolution of the synoptic maps, the footpoints of X-ray loops are almost always rooted in locally strong magnetic concentrations and also in extra-dark 1083 nm elements.
