Theoretical, experimental and numerical simulation study of a radially injected barium disk

Thesis (M.S.) University of Alaska Fairbanks, 1981An Investigation of the dynamics and stability of a high-altitude radial barium plasma injection is performed using theoretical and numerical simulation methods. The barium plasma cloud, injection experiment was conducted on March 16, 1980 and produced several interesting phenomena: (1) Three distinct rings of barium containing irregularities exhibiting collective motion; (2) A region of plasma depletion at the location of injection; (3) A structure of approximately eighteen distinct barium ion rays emanating from the injection location. A collisionless, electrostatic particle simulation model is used to understand the behavior of the plasma, indicating that the initial plasma deformation develops due to an E x B azimuthal velocity shear instability. A theoretical model used for a stability analysis of the plasma is formulated based on the number density distributions of the electrons and ions obtained from the numerical simulation results. The linear stability analysis shows that the number of unstable azimuthal modes created by the velocity shear instability is dependent upon the amount of charge separation occurring in the expanding plasma