Studies on ion acoustic wave interaction in laboratory dusty plasma system

Abstract

This thesis is aimed to make an arrangement for the production of dusty plasma in laboratory and study the basic properties of dusty plasma as well as the nonlinear phenomena like, sheath and ion acoustic wave propagation in multi-component dusty plasma. The dusty plasma is a plasma which comprises not only ions and electrons, but a significant density of dust grains. The dust grains themselves can be anything from simple ice particulates, such as in cometary tails and in various space and astrophysical plasmas, to almost anything capable of sustaining an electric charge. Dust surrounded by an ionized medium, is obviously a special case. As the plasma affects the dust particles, the dust particles can also affect the plasma environment. They exhibit new and unusual behaviour, and provide a possibility for modified or entirely new collective models of oscillations and instabilities, as well as coherent nonlinear structures. The experimental arrangement used to produce dusty plasma is a so called double plasma device equipped with multiple magnets for surface plasma confinement where a dust dispersing setup is suitably mounted. The dust dispersing setup consists of an ultrasonic vibrator attached to a dust reservoir and the by adjusting the voltage to the vibrator dust density into the plasma can be varied. As the dust particles are allowed to fall into the Ar plasma they get charged due to the collection of electron and ion from the background plasma. When intergrain distance between dust particles becomes smaller than the Debye length, dusty plasma is produced. To produce multi-component plasma with negatively charged dust particles and negative ions, SF6 gas is introduced into the dusty plasma. The SF6 molecule is bombarded by the electrons of the plasma, which mainly leads to the formation of F ions due to dissociative attachment process and multi-component plasma with dust and negative ions is generated. In order to study the sheath phenomena in dusty plasma, a stainless steel plate is placed inside the...