Nonlinear responses in dusty plasmas.
Dusty plasma as a system containing both plasmas and dust particles. Dusty plasma systems are found throught out the industy and the space, for example, dust are found in plasma etching and in TOKAMAKs, as well as Saturn rings. Thus, the study of dusty plasma helps to understand many systems in reality. In this dissertation, the interaction of dust particles in a plasma sheath has been studied to determined the nature of the non-linear interaction. Theoretical model for describing the nonlinear dust interaction has been established and used to explain experimental observations. This dissertation is arranged in the following way. In chapter one, a background introduction of dusty plasmas is provided. In chapter two, a theoretical model describing the motion of two coupled dust particles considering nonlinear particle-particle interaction is established, and a perturbation method is used to analytically solve this model. In chapter three, experiments measuring amplitude-frequency responses are introduced and the nonlinear interaction is studied based on the model established in chapter two. In chapter four, the model established in chapter two is extended to a higher degree of freedom, which explains the ‘internal resonance’ that is observed for the first time in dusty plasma. In chapter five, a Bayesian optimization-based automatic method for response analysis of a single dust particle is proposed. In chapter six, a quick estimation method is proposed for measuring the charge of dust particles in the plasma sheath.