2000/02/23 by D. Proga, Daniel Proga · 3 citations
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astro and Planetary Science #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Optics #Physics #Radiation #astro-ph
paper · pdf · doi:10.1086/309154
LaTeX, 11 pages, 6 color postscript or PJEG files, to appear in ApJ
arxiv created 2000/02/23 · openalex publication_date 2000/08/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the 2-D, time-dependent hydrodynamics of radiation-driven winds fromluminous accretion disks threaded by a strong, large-scale, ordered magneticfield. The radiation force is due to spectral lines and is calculated using ageneralized multidimensional formulation of the Sobolev approximation. Theeffects of the magnetic field are approximated by adding a force that emulatesa magnetocentrifugal force. Our approach allows us to calculate disk winds whenthe magnetic field controls the flow geometry, forces the flow to corotate withthe disk, or both. In particular, we calculate models where the lines of thepoloidal component of the field are straight and inclined to the disk at afixed angle. Our numerical calculations show that flows which corotate with thedisk have a larger mass loss rate than their counterparts which conservespecific angular momentum. The difference in the mass loss rate between thesetwo types of winds can be several orders of magnitude for low disk luminositiesbut vanishes for high disk luminosities. Winds which corotate with the diskhave much higher velocities than angular momentum conserving winds. Fixing thewind geometry stabilizes winds which are unsteady when the geometry is derivedself-consistently. The inclination angle between the poloidal velocity and thenormal to the disk midplane is important. Non-zero inclination angles allow themagnetocentrifugal force to increase the mass loss rate for low luminosities,and increase the wind velocity for all luminosities. Our calculations also showthat the radiation force can launch winds from magnetized disks. The line forcecan be essential in producing MHD winds from disks where the thermal energy istoo low to launch winds or where the field lines make an angle of < 30o withrespect to the normal to the disk.