Effect of ion beam current on dust charge fluctuations and ion-acoustic waves in electronegative dusty plasmas

Abstract

The effects of ion beam current associated with the streaming positive ions on the dust charge fluctuations and ion acoustic wave propagation in quiescent electronegative dusty plasma have been investigated using fluid theory. The dust charging phenomenon and unstable mode of ion waves are modified for two streaming conditions of positive ions which are extended and graphically illustrated. The dependencies of the growing and damping rate of ion waves on dust density and the size of dust grains are studied. The evolution of dust surface potential is found in the negative domain with the increase in concentration of negative ions and the instability rate for ion wave decreases. Furthermore, it is shown that the dust surface potential shifts into positive domain as the electrons are significantly depleted (and the plasma becomes ion-ion plasma) from the electronegative plasma and thus ion waves exhibit a damping phenomenon.

Nonlinear dust-ion acoustic solitary waves for collisional electronegative dusty plasma in the presence of trapped electron distribution

“…The equilibrium dust charge is obtained when the dust charging process is constant with time. The equation (12) becomes I i0 + I e0 + I n0 = 0. For the negatively charged dust grains, the equilibrium current contributed by trapped electrons I e0 ( ), positive and negatives ions I I , i0 n0 ( ) are based on orbital motion limited (OML) theory are [41][42][43][44]: respectively.…”

“…Since the thermal velocity of electrons is higher than that of positive and negative ions, the dust grains acquire initially negative charge which accelerates the slower positive ions but later, it will repel the negative ions and electrons as well. In most of the man-made and naturally occurring dusty plasma system, the number density of electrons are depleted during the various process (for example, electron flux loss to the dust grain's surface, electron-ion recombination) and electronegative dusty plasma becomes a pair-ion dusty plasma, which exhibits markedly novel characteristics because of the negative ions are much heavier than that of electrons [9,12]. As the electrons are significantly depleted from the electronegative dusty plasma, the negativity of dust charge could shift towards the positive domain, that means the dust grains acquire less negative charges due to reduced population of electrons [9].…”