We define superthermal plasma nodules as bright points (diameter ~< 710"), visible on high resolution X-ray heliograms. Flares appear to show a strong tendency to occur at the places of these nodules. There are indications that (part of) the hot plasma produced by consecutive flares is accumulated and confined in the superthermal plasma nodules, and that with increasing energy content of a nodule the probability for a drastic change of its magnetic structure increase:s, thus reducing the possibility for more flares to occur.

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Examination of X-ray images obtained by the S-054 X-ray spectrographic telescope on Skylab shows the presence of some atypical X-ray emitting coronal structures in active regions which are not consistent with potential extrapolations of photospheric magnetic fields. Analysis of the observed temporal changes in the X-ray emitting active region structures demonstrates that the majority of these consist of brightness changes representing temperature (and perhaps, density) variations of the material in the loops.

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