Magnetic Forces in an Isopedic Disk

Details Magnetic Forces in an Isopedic Disk Magnetic Forces in an Isopedic Disk

Jan 1997

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997apj...475..251s&link_type=abstract

Astrophysical Journal v.475, p.251

Astronomy and Astrophysics

Astronomy

66

Magnetohydrodynamics: Mhd

Scientific paper

We consider the magnetic forces in electrically conducting thin disks threaded by magnetic fields originating in the external (interstellar) medium. We focus on disks that have dimensionless ratios lambda of the mass to flux that are spatially constant, a condition that we term isopedic. For arbitrary distributions of the surface density Sigma (which can be nonaxisymmetric and time dependent), we show that the magnetic tension exerts a force in the plane of the disk equal to -1/ lambda 2 times the self-gravitational force. In addition, if the disk maintains magnetostatic equilibrium in the vertical direction, the magnetic pressure, integrated over the z-height of the disk, may be approximated as (1 + eta 2)/( lambda 2 + eta 2) times the gas pressure integrated over z, where eta = f||/2 pi G Sigma and f|| is the component of the local gravitational field parallel to the plane of the disk. We apply these results to the problem of the stability of magnetized isothermal disks to gravitational fragmentation into subcondensations of a size comparable to the vertical scale height of the disk. Contrary to common belief, such dynamical fragmentation probably does not occur. In particular, the case of the magnetized singular isothermal disk undergoes not dynamical fragmentation into many subcondensations, but inside-out collapse into a single compact object, a self similar problem that is studied in a companion paper (Li & Shu 1997).

Affiliated with

Also associated with

No associations

Rating

Magnetic Forces in an Isopedic Disk 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 Forces in an Isopedic Disk, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic Forces in an Isopedic Disk will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1785911