Driven dust-charge fluctuation and chaotic ion dynamics in the plasma sheath and presheath regions.

Abstract

Possible existence of chaotic oscillations in ion dynamics in the sheath and presheath regions of a dusty plasma, induced by externally driven dust-charge fluctuation, is presented in this work. In a complex plasma, dust charge fluctuation occurs continuously with time due to the variation of electron and ion currents flowing into the dust particles. In most of the works related to dust-charge fluctuation, theoretically it is assumed that the average dust-charge fluctuation follows the plasma perturbation, while in reality, the dust-charge fluctuation is a semirandom phenomenon, fluctuating about some average value. The very cause of dust-charge fluctuation in a dusty plasma also points to the fact that these fluctuations can be driven externally by changing electron and ion currents to the dust particles. With the help of a hybrid-particle in cell-Monte Carlo collision (h-PIC-MCC) code in this work, we use the plasma sheath as a candidate for driving the dust-charge fluctuation by periodically exposing the sheath-side wall to UV radiation, causing photoemission of electrons, which in turn drive the dust-charge fluctuation. We show that this driven dust-charge fluctuation can induce a chaotic response in the ion dynamics in the sheath and the presheath regions.