On the occurrence of stream overflow in cataclysmic variables with accretion disks

I consider the occurrence of the flow of accretion stream material past the edge of an accretion disk in cataclysmic variables. If the stream from the secondary star is geometrically thicker than the rim of the accretion disk , some fraction of the stream material can flow over and under the disk. Th e results of vertical-structure calculations for a-model disks indicate tha t the amount of overflow is a sensitive function of the general thermal sta te of the disk (e:.g., cold and optically thick or warm and optically thin) but not of the value of the disk viscosity parameter cl and probably not o f the disk radius (i.e., the orbital period). Using the mass-transfer rates and the orbital parameters of well-studied systems, I estimate the amount of overflow for a number of individual objects and show that observationall y significant stream overflow should mainly occur in quiescent dwarf novae with cold outer disks.