Magnetic shear-driven instability and turbulent mixing in magnetized protostellar disks
INAF – Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy e-mail: firstname.lastname@example.org
2 INFN, Sezione di Catania, via S. Sofia 72, 95123 Catania, Italy
3 A.F. Ioffe Institute of Physics and Technology and Isaac Newton Institute of Chile, Branch in St. Petersburg, 194021 St. Petersburg, Russia
Accepted: 5 December 2007
Context.Observations of protostellar disks indicate the presence of the magnetic field of thermal (or superthermal) strength. In such a strong magnetic field, many MHD instabilities responsible for turbulent transport of the angular momentum are suppressed.
Aims.We consider the shear-driven instability that can occur in protostellar disks even if the field is superthermal.
Methods.This instability is caused by the combined influence of shear and compressibility in a magnetized gas and can be an efficient mechanism to generate turbulence in disks.
Results.The typical growth time is of the order of several rotation periods.
Key words: accretion, accretion disks / magnetohydrodynamics (MHD) / instabilities / turbulence / stars: formation
© ESO, 2008