Magnetically Driven Warping, Precession and Resonances in Accretion Disks

摘要: The inner region of the accretion disk onto a rotating magnetized central star (neutron star, white dwarf or T Tauri star) is subjected to magnetic torques which induce warping and precession disk. origin these lies in interaction between (induced) surface current on horizontal field (parallel disk) produced by inclined dipole. Under quite general conditions, there exists instability torque drives plane away from equatorial toward state where normal vector perpendicular spin axis. Viscous stress tends suppress at large radii, but always dominates as approaches magnetosphere boundary. also tilted into retrograde around stellar Moreover, resonant forcing can occur may affect dynamics magnetically driven be related number observational puzzles, including: (1) Spin evolution (torque reversal) accreting X-ray pulsars; (2) Quasi-periodic oscillations low-mass binaries; (3) Super-orbital periods (4) Photometric period variations stars.