The instability of hydromagnetic planetary-gravity waves in a zonal flow and transverse magnetic field

✍ Scribed by O. M. Mekki

• Publisher: Springer
• Year: 1983
• Tongue: English
• Weight: 387 KB
• Volume: 85
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00148259

✦ Synopsis

Hydromagnetic planetary-gravity waves propagating on a B-plane through a zonal flow and transverse magnetic field are examined for instability. Such instabilities may be related to same physical phenomena in the atmospheres of the Sun and planets and in the Earth's core. It is found that the onset of instability depends on the directions of the vertical and transverse wave-numbers and the zonal flow. It is also shown that as the magnetic field intensity is kept uniform instability can onset provided that the zonal flow strength does not exceed a certain factor, which depends on the parameters of the medium, and then the zonal wavenumbers that can become unstable are limited to a given range.

If the basic Alfv6n wave speed is allowed to vary whereas the zonal flow is kept uniform the zonal wavenumbers that can exhibit instability are again limited but the basic Alfv6n wave speed can assume any value.