Radiation-driven accretion disk winds

The concept of an ‘effective' Eddington limit as a lower bound on the system luminosity required for mass loss to be radiation pressure driven is discussed and shown to fall in the interesting regime for high-state non-magnetic CV (nMCV). The results of recent hydrodynamical models of radiation-driven disk winds (Proga et al. 1998, Proga 1999) are summarised. Mass loss rates predicted by these models are then compared with observational constraints. It is shown that either mass accretion rates in high-state nMCV are a factor of 2–3 larger than presently supposed or that radiation pressure alone is not quite sufficient to drive the observed hypersonic flows.