Puffy disks combine features of thin, slim, and thick
disk but differs in crucial respects from each of them. These solutions
provide a realistic description of black hole accretion in mildly
sub-Eddington regime. By the density scale-height measure the disk
appears to be thin, having a high density core near the equatorial
plane, but most of the inflow occurs through a highly advective,
turbulent, optically thick, Keplerian region that sandwiches the
core and has a substantial geometrical thickness comparable
to the radius. The accreting fluid is supported above the midplane
in large part by the magnetic field, with the gas and radiation
to magnetic pressure ratio around 1, this makes the disk thermally
stable, even though the radiation pressure strongly dominates over
gas pressure. A significant part of the radiation emerging from
the disk is captured by the black hole, so the disk is less
luminous than a thin disk would be at the same accretion rate.
The extended vertical structure of the disk has significant
consequences on the observational picture of the acreeting system.
