Existence and stability of modulated dust-acoustic wave packets in the presence of nonthermal ions

Abstract

The effects of dust temperature and energetic (nonthermal) ions are incorporated in the study of modulated instability of dust-acoustic (DA) waves in a dusty plasma containing warm adiabatic dust grains, isothermal electrons and hot ions obeying a nonthermal distribution. Based on the multiple space and time scales perturbation, a nonlinear Schrödinger equation is derived with a solution showing a new relationship between the modulated DA wave packets and ion nonthermality. It is shown that as the population of fast ions increases, the transition from stable dark envelope solitons to unstable ones shifts to the smaller wavelength regions. The instability growth rate reduces owing to the presence of nonthermal ions. It is also found that the effects of dust temperature and electron concentration modify the criteria for the modulational instability of DA waves. The results could be useful for understanding the properties of modulated wave packets and their evolution in space and laboratory dusty plasmas, such as those in and around the Earth’s foreshock.