The Universe is made up of systems consisting of a very large number of particles interacting in a very complex way. When studying these systems, a precise microscopic approach is unattainable. In practice, the best strategy is one that is able to “distinguish” between superfluous information and the information needed to make predictions about the evolution of the system. There are two main competing approaches: kinetic and hydrodynamic. Collective Phenomena in Plasmas and Elsewhere presents an overview of the theoretical bases of these kinetic and hydrodynamic approaches, but also discusses their limitations, the links between them and their extension to quantum mechanics and relativity. These methods were born in part out of the study of plasmas, but they also have more universal applications. A general framework for these approaches is outlined, followed by some applications in plasmas, gravitation, Bose–Einstein condensates and dark matter. Particular emphasis is placed on the analogies that can be made between all these different systems.

The Universe is made up of systems consisting of a very large number of particles interacting in a very complex way. When studying these systems, a precise microscopic approach is unattainable. In practice, the best strategy is one that is able to “distinguish” between superfluous information and the information needed to make predictions about the evolution of the system. There are two main competing approaches: kinetic and hydrodynamic. Collective Phenomena in Plasmas and Elsewhere presents an overview of the theoretical bases of these kinetic and hydrodynamic approaches, but also discusses their limitations, the links between them and their extension to quantum mechanics and relativity. These methods were born in part out of the study of plasmas, but they also have more universal applications. A general framework for these approaches is outlined, followed by some applications in plasmas, gravitation, Bose–Einstein condensates and dark matter. Particular emphasis is placed on the analogies that can be made between all these different systems.

The objective of this research was to find experimental evidence of an 'anomalous' resistance in plasmas. Anomalous resistance results when collective action by electrons causes randomization of the growing oscillations in the two-stream instability. This sequence of events leading to dissipation of energy was predicted several years ago by Buneman. It is believed that this objective was achieved (i.e., that anomalous resistance is evidenced by observations to be reported here), on a high density plasma subjected to r-f fields by a cavity resonant at a frequency well below the plasma frequency. With sufficient r-f power and density, the two-stream instability should be excited to turbulence level during each halfcycle, causing irreversible power loss. Calculations enumerating the necessary conditions for observing the phenomena were made, showing that the resistance can easily be seen above the intrinsic cavity loss using very moderate amounts of power. (Author).

I also find that the compressibility, a measure of the coupling between the dust particles, have a strong effect on the wave propagation. Comparing the kinetic vs. hydrodynamic descriptions for ions, I find that under typical laboratory conditions the inverse Landau damping and the ion-neutral collisions contribute about equally to the dust acoustic instability. Third, I performed dust acoustic wave experiments to resolve a previously unremarked discrepancy in the literature regarding the sign of the compressibility of a strongly-coupled dust component in a dusty plasma. According to theories compressibility is negative, whereas experiments suggest that it is positive. I find that the compressibility is positive. This conclusion was reached after allowing for a wide range of experimental uncertainties and model dependent systematic errors. Finally, the polygon construction method of Glaser and Clark was used to characterize crystallization and melting in a single-layer dusty plasma. Using particle positions measured in a previous dusty plasma experiment, I identified geometrical defects, which are polygons with four or more sides. These geometrical defects are found to proliferate during melting. I also identify a possibility of latent heat involvement in melting and crystallization processes of a dusty plasma.