Truncated disks - advective tori; new solutions of accretion flows around black holes

Our quasi-steady 2D numerical radiative hydrodynamical investigations of tw o-temperature accretion flows around black holes indicate that standard dis ks are thermally and hydrodynamically stable against transition to opticall y thin disks at large radii. Optically thin disks cool sufficiently rapid a t large radii inducing a vertical collapse and forming thereby a standard d isk which truncates close to the last stable orbit. In the absence of soft photons from the adjusting standard disk, we confirm the runaway cooling of the inner optically thin disk. This runaway however terminates if the radi al flux of soft photons from the outer standard disk is taken into account. Instead, a cooling-driven front starts to propagates from outside-to-insid e continuously extending the thick disk down to the very inner region where it terminates via an oppositely-oriented heating front that forms a hot ad vective and sub-keplerian torus. The transition between the two configuration occurs where the ratio of the cooling to the heating time attains a minimum value. The transition is foun d to be rather sharp and gives rise to outwards-oriented motions of very ho t plasma that enlarges the combined Compton-Synchrotron cooling regions con siderably. While the disk-torus configuration obtained depends weakly on whether the f low is a one or two-temperature plasma, one-temperature tori are hotter and fill larger volumes than their two-temperature counterparts.