Shear Alfven-like waves in a weakly ionized self-gravitating nonuniform dusty magnetoplasma

The dispersion properties of obliquely propagating ultra-low-frequency electromagnetic shear Alfven-like waves in a weakly ionized, self-gravitating, nonuniform dusty magnetoplasma are examined. It is found that the electromagnetic shear Alfven-like waves having the wavelength of the order of 10 AU and the wave period of the order of 30 000 years are unstable due to the effect of the self-gravitational force acting on the dust grains. The present investigation may be of relevance to the regions (namely, warm photodisassociation regions) at the boundary between molecular clouds and H II regions surrounding hot early type stars. (C) 2001 American Institute of Physics.