Waves and instabilities in dark interstellar molecular clouds containing ferromagnetic dust grains
A. A. Mamun, P. K. Shukla
Institut für Theoretische Physik IV, Fakultät für Physik und Astronomie,
Ruhr Universität Bochum, D-44780 Bochum, Germany
PACS: 98.38.Am
Abstract
The propagation characteristics of magnetization waves as well as
the instabilities of sound waves in a self-gravitating dark interstellar
molecular cloud containing ferromagnetic dust grains and baryonic gas clouds
have been theoretically investigated by including the dynamics of both
ferromagnetic dust grains and baryonic gases. It has been shown that there
exist two types of subsonic or supersonic (depending on the field stength of
the magnetization) tranverse magnetization waves, which can be regarded as
counterparts of Alfvén waves (for the parallel propagation) and of
magnetosonic waves (for the perpendicular propagation) in a magnetoactive
plasma. It has also been found that in addition to the usual Jeans
instability, the sound waves suffer a new type of instability which is due to
the combined effects of the baryonic gas dynamics and self-gravitational
field in both weakly and highly collisional regimes.