On stereoimages of some structures in the solar atmosphere

Three-dimensional structures in the solar chromosphere and corona are consi dered. It is demonstrated that two photoheliograms separated by similar to 1 day can be used (using computer-graphics methods) to construct a stereo i mage of the Sun. The algorithm for this is presented and carried out for H- alpha images of the total disk. A bulge in the equatorial region resulting from the differential rotation of the Sun can be seen in the stereo image. Structures called Whitney pleats in catastrophe theory are observed in the solar corona. Such structures are encountered in prominences. The well-know n helmets (or streamers) are pleats of heliospheric plasma sheets. Isophote s for such a sheet and the degree of polarization of the radiation in the p leat are calculated and compared with observational data. (C) 2000 MAIK "Na uka/Interperiodica".