Princeton University Thunch Talk

Accretion is a ubiquitous process is the universe, shaping objects from planets to supermassive black holes. For accreters which posses a material surface, the accretion flow rapidly change configurations from a rotationally supported disk to the slowly rotating pressure supported accreter atmosphere. In the case where the magnetic field of the accreter is insufficient to interrupt the accretion disk, the accreted material is transported through the narrow boundary layer joining the accretion disk to its accreter. Due to a change in angular momentum gradients the magnetorotational instability is unable to operate in the boundary layer. Using recent high resolution simulations of the boundary layer I elucidate the physical processes transporting angular momentum and material through the boundary layer, and discuss the appearance of quasi-periodic oscillations in these simulations which my explain the observed dwarf nova oscillations.