We present a model for the dispersal of protoplanetary disks by winds from either the central star or the inner disk. These winds obliquely strike the flaring disk surface and strip away disk material by entraining it in an outward radial-moving flow at the wind-disk interface which lies several disk scale heights above the mid-plane. The disk dispersal time depends on the entrainment velocity,...

We consider the inner regions of accretion disks surrounding black holes and neutron stars and investigate the nonlinear time dependent evolution of thermal-viscous instabilities. The viscous stress is assumed to be proportional to the gas pressure with the viscosity parameter formulated as α = min[α0(h/r) , αmax], where h is the local scale height, r is the distance from the central compact ob...

We present a pseudo-Newtonian potential for accretion disk modeling around the rotating black holes. This potential can describe the general relativistic effects on accretion disk. As the inclusion of rotation in a proper way is very important at an inner edge of disk the potential is derived from the Kerr metric. This potential can reproduce all the essential properties of general relativity w...

We describe the most general nature of accretion and wind flows around a compact object and emphasize on the properties which are special to black hole accretion. The angular momentum distribution in the most general solution is far from Keplerian, and the nonKeplerian disks can include standing shock waves. We also present fully time dependent numerical simulation results to show that they agr...

With the fundamental stress mechanism of accretion disks identified—correlated MHD turbulence driven by the magneto-rotational instability—it has become possible to make numerical simulations of accretion disk dynamics based on well-understood physics. A sampling of results from both Newtonian 3-d shearing box and general relativistic global disk MHD simulations is reported. Among other things,...

This is the first paper in a series where we study the influence of turbulent diffusion and advective transport on the chemical evolution of protoplanetary disks, using a 2D flared disk model and a 2D mixing gas-grain chemical code with surface reactions. A first interesting result concerns the abundance of gasphase CO in the outer regions of protoplanetary disks. In this Letter we argue that t...