Non-ideal effects in dusty plasmas

Electrostatic waves and instabilities in weakly non-ideal magnetized dusty plasmas have been investigated by incorporating the van der Waals equation of state as well as the grain charging equation. For the homogeneous case, the propagation of linear dust-acoustic waves (DAWs) has been considered. It is found that the volume reduction coefficient enhances the DAW phase speed while the molecular attractive forces lead to a decrease in the speed. In the high temperature limit, there is a net increase in the DAW phase speed while near the critical point the phase speed is reduced. Inhomogeneous magnetized dusty plasmas support density as well as temperature gradient driven electrostatic drift waves in the low-frequency regime. On the other hand, when shear flows are present, dusty plasmas are susceptible to (parallel) Kelvin-Helmholtz (K-B) instabilities. In addition to the usual density gradient driven K-H (DGKH) instability, we point out the existence of a new type of temperature gradient driven K-H (TGKH) instability. At higher frequencies near the dust-gyro frequency, electrostatic dust cyclotron waves (EDCWs) can be driven unstable due to sheared flows. In all cases, dust charge fluctuations lead to damping effects, thereby reducing the instability growth rates.