Spiral waves and instability in magnetized astrophysical disks

Journal Article · Sun Apr 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168655· OSTI ID:6806694

Tagger, M; Henriksen, R N; Sygnet, J F; Pellat, R ^[1]

---

1. CEA, Service d'Astrophysique, Gif-sur-Yvette (France) CNRS, Institut d'Astrophysique, Paris (France) Ecole Polytechnique, Palaiseau (France)

It is shown that an ionized disk in a vertical magnetic field (e.g., the dipole field of the central object for an accretion or planetary disk) is subject to spiral instabilities of low azimuthal wavenumber, driven by differential rotation. The amplification is due to the Swing mechanism already known for the spiral instability of galactic disks, with self-gravity replaced by magnetic forces. In realistic cases the growth time is a few tens of rotation periods. Such instabilities, or waves driven by irregularities in the ambient magnetic field, might be important in particular for accretion disks, and to explain the spokes in Saturn's rings. 11 refs.

• OSTI ID: 6806694
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 353; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
640107 -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
ATMOSPHERES
FLUID MECHANICS
GRAVITATIONAL FIELDS
HYDRODYNAMICS
INSTABILITY
MAGNETIC FIELD CONFIGURATIONS
MAGNETOHYDRODYNAMICS
MECHANICS
MOTION
PLANETARY ATMOSPHERES
PLANETARY MAGNETOSPHERES
PLANETS
RINGS
ROTATION
SATURN PLANET
STABILITY