Mathematics
Scientific paper
May 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995apj...445..337l&link_type=abstract
The Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 445, no. 1, p. 337-347
Mathematics
43
Accretion Disks, Angular Momentum, Energy Distribution, Kinetic Energy, Magnetic Field Configurations, Magnetic Fields, Rotation, Stability, Analysis (Mathematics), Dispersing, Magnetic Effects, Pressure Distribution, Shear Properties, Velocity Distribution
Scientific paper
We investigate the stability of a disk to magnetic interchange in the disk plane, when a poloidal magentic field provides some radial support of the disk. The disk is assumed to be geometrically thin and may possess rotation and shear. We assume the unperturbed magnetic field vertically threads the disk and has a comparable radial component at the disk surface. We formulate the linear stability problem as an initial value problem in shearing coordinates and ignore any effects of winds. Shear stabilizes the interchange instability strongly compared to the uniformly rotating case studied previously and makes the growth algebraic rather than exponential. A second form of instability with long wavelengths is identified, whose growth appears to be transient. If the field strength is measured by the travel time tauA of an Alfven wave across the disk thickness, significant amplification for both forms of instability requires (tauA Omega)-2 greater than or approximately equal to L/H, where L is the radial length scale of the field gradient and H is the disk thickness. Field strengths such that 1 less than or approximately equal (tauA Omega)-2 less than or approximately equal L/H are stable to these instabilities as well as the instability recently investigated by Balbus & Hawley (1991). The results suggest that in dark environments in which the magnetic energy density is greater than the thermal energy density, disks are stable over a substantial range of parameter space, with radial advection of magnetic flux limited by the interchange instability possibly near the disk center. Such environments may be relevant for the production of magnetic winds or jets in young stars or active galactic nuclei.
Lubow Stephen H.
Spruit Hendrik C.
No associations
LandOfFree
Magnetic interchange instability in accretion disks does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Magnetic interchange instability in accretion disks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic interchange instability in accretion disks will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1059189