Fundamental Particle and Wave Dynamics in Dusty Plasmas.

摘要

Dusty plasma is a low-temperature plasma containing dust particles varying in size from nanometers to micrometers. Due to plasma fluxes to its surface, a dust particle will charge negatively or positively depending on the charging mechanism involved. The motion of a dust particle within a dusty plasma can be recorded using a video camera, allowing for examination of the particle dynamics at the kinetic level.;Any investigation of dusty plasmas first requires a proper understanding of the fundamental particle-particle interaction, dust particle charge and screening length. Due to the perturbative nature of the majority of diagnostics in common use, all of these are difficult to measure properly.;Each of the fundamental parameters mentioned above are addressed in this thesis. First a minimally perturbative technique, allowing experimental detection of each of these parameters, will be introduced. Next, a study of vertically aligned, extended dust particle chains employing a glass box placed on the lower powered electrode in a ground-based RF plasma system will be discussed. Finally, by adjusting the discharge power and the gas pressure within the plasma chamber, it will be shown that a chaotic dust cloud can form such vertical chains as well as self-excited dust acoustic waves. An investigation of both the particle and wave dynamics within various sizes of glass box and under a number of plasma conditions will be presented. A theoretical model is also introduced providing a comprehensive dispersion relationship for dust acoustic waves (DAWs) and examining the instabilities resulting from the effects created by the dust temperature, particle charge variation, and ion-drag-force fluctuations. It is shown that each plays a different role depending on the wavelength regime considered.