  Modeling of the x-ray spectra of the Galactic superluminal jet sources GRS
1915+105 and GRO J1655-40 reveal a three-layered atmospheric structure in the
inner region of their accretion disks. Above the cold and optically thick disk
of a temperature 0.2-0.5 keV, there is a warm layer with a temperature of
1.0-1.5 keV and an optical depth around 10. Sometimes there is also a much
hotter, optically thin corona above the warm layer, with a temperature of 100
keV or higher and an optical depth around unity. The structural similarity
between the accretion disks and the solar atmosphere suggest that similar
physical processes may be operating in these different systems.
