Kinetic dust acoustic mode in inhomogeneous partially magnetized plasma

The dust acoustic mode in inhomogeneous plasmas is discussed in the regime when the electrons and ions are magnetized while at the same time the dust grains remain un-magnetized. Although the dynamics of the light species is strongly affected by the magnetic field, the dust acoustic mode may still propagate in practically any direction. The inhomogeneity implies a source of free energy for an instability that develops through the diamagnetic drift effects of the magnetized species. It is shown that this may be a powerful mechanism for the excitation of dust acoustic waves. The analysis presented in this work is also applicable to plasmas containing both positive and negative ions and electrons, provided that at least one of the two ion species is un-magnetized.status: publishe