The Magnetic Thermal Wind and Differential Rotation of Ionized, Magnetic Atmospheres
Abstract
Slow motions of an ideal, ionized, rotating fluid in the presence of a nonconstant magnetic field are investigated. A magnetic analog to the thermal wind is found when the fluid is compressible. Vertical variations of the longitudinal fluid velocity are shown to result from a latitudinal gradient in magnetic field in such a manner that the angular velocity of the fluid decreases with height whenever the absolute value of non-force-free magnetic fields increases poleward. A second order contribution to this "magnetic thermal wind" is produced by vertical variations in the magnetic field. It is suggested that the magnetic thermal wind can have an important effect on the rotation rate of a stellar atmosphere and may be partially responsible for the apparent slow rotation rate of magnetic A type stars. Subject headings: hydromagnetics - rotation
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1975
- DOI:
- 10.1086/153913
- Bibcode:
- 1975ApJ...201..509G