Electrodynamics and dispersion properties of a magnetoplasma containing elongated and rotating dust grains

The electrodynamics and dispersion properties of a magnetized dusty plasma containing elongated and rotating charged dust grains are examined. Startin g from an appropriate Lagrangian for dust grains, a kinetic equation for th e dust grain and the corresponding equations of motion are derived. Express ions for the dust charge and dust current densities are obtained with the f inite size (the dipole moment) of elongated and rotating dust grains taken into account. These charge and current densities are combined with the Maxw ell-Vlasov system of equations to derive dispersion relations for the elect romagnetic and electrostatic waves in a dusty magnetoplasma. The dispersion relations are analyzed to demonstrate that the dust grain rotation introdu ces new classes of instabilities involving various low-frequency waves in a dusty magnetoplasma. Examples of various unstable low-frequency waves incl ude the electron whistler, the dust whistler, dust cyclotron waves, Alfven waves, electromagnetic ion-cyclotron waves, as well as lower-hybrid, electr ostatic ion cyclotron, modified dust ion-acoustic waves, etc. Also found is a new type of unstable waves whose frequency is close to the dust grain ro tation frequency. The present results should be useful in understanding the properties of low-frequency waves in cosmic and laboratory plasmas that ar e embedded in an external magnetic field and contain elongated and rotating charged dust grains. (C) 2001 MAIK "Nauka/Interperiodica".