Abstract
The basic characteristics of linear magnetohydrodynamic (MHD) waves in a self-gravitating, rotating, magnetized plasma are examined. It is shown that for Cs2<πρG/k the phase speed of the fast wave decreases with increasing θ, the angle between the magnetic field and wave vectors. In addition, slow mode waves become unstable and may possibly possess a positive density-magnetic field correlation like the fast mode. One implication is that the observed phase relationship between the magnetic field and density spiral arms cannot be used as a sole criterion for the identification of slow and fast MHD density waves in rotating thin discs.
| Original language | English |
|---|---|
| Pages (from-to) | 1095-1097 |
| Number of pages | 3 |
| Journal | Physics of Plasmas |
| Volume | 8 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2001 |