Fundamental particle and wave dynamics in dusty plasmas.

Zhang, Zhuanhao.
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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.

Fundamental particle and wave dynamics.