Instability of dust acoustic wave due to nonthermal ions in a charge varying dusty plasma

Abstract

The effects of nonthermal ions with excess of fast (energetic) ions on linear dust acoustic (DA) wave propagation has been investigated incorporating the dust charge variation and the isothermal dust pressure variation. It is seen that due to the dust charge variations in the presence of nonthermal ions, instead of the usual damping, there is a growth of the DA wave if the ion nonthermality parameter a>15(1+σi)/(8−72σi), σi(=Ti/Te≪1), Ti(Te) is the ion (electron) temperature, and there may occur, under certain conditions, exponentially growing mode with zero real frequency. It is also seen that in the absence of dust charge variations there also occurs a zero real frequency, exponentially growing mode if the ion nonthermality parameter a>1. In absence of dust charge variations or in the presence of adiabatic dust charge variations, finite dust temperature Td can stabilize the instability. However, in the presence of nonadiabatic dust charge variations Td cannot stabilize the instability.