Effect of strong coupling on dust acoustic waves and instabilities

Abstract

The presence of charged dust in a plasma can lead to very low frequency dust acoustic waves and instabilities. In certain laboratory plasmas the dust is strongly coupled, as characterized by the condition Γd=Qd2 exp(−d/λD)/dTd⩾1, where Qd is the dust charge, d is the intergrain spacing, Td is the dust thermal energy, and λD is the plasma screening length. When the dust is strongly coupled, the spatial correlation of the grains can affect the dispersion relation of these waves. We review our recent work [1] on the dispersion properties of dust acoustic waves in the strongly coupled (liquid) phase in a dusty plasma, including also the effects of dust-neutral collisions. We then discuss a preliminary analysis of the effect of strong dust coupling on an ion dust two-stream instability in a collisional dusty plasma. Applications to laboratory dusty plasmas are discussed.