  Rather than accreting via a disk, some White Dwarfs (WDs) in quiescent Dwarf
Novae (DN) could accrete via an Advection-Dominated Accretion Flow (ADAF)
possibly responsible for the X-ray Bremsstrahlung emission observed. Such a hot
accretion flow is also expected to produce characteristic thermal line
emission. Using SS Cyg as a specific example, we show that knowing a priori the
inclination and the WD mass in quiescent DN makes X-ray line diagnostics
powerful probes of the flow structure in these systems. Current X-ray
instruments can discriminate, from their width, between lines emitted from a
flow with a Keplerian rotation rate and those emitted at a substantially
sub-Keplerian rate. This could be used to observationally test the property of
energy advection, which is at the origin of the partial radial pressure support
by the hot gas and the sub-Keplerian rotation rate in an ADAF.
