Turbulence and transport in mirror geometries in the LAPD

Measurements of turbulence and transport in varying magnetic mirror ratios have been performed using the flexible magnetic geometry of the Large Plasma Device (LAPD). Fluctuations in density (ion saturation current), floating potential, and magnetic field were recorded, with amplitudes peaking, as expected, on the edge pressure gradient. Planar correlation functions were also recorded. Density and magnetic field fluctuation amplitudes decreased with increasing mirror ratio, while potential fluctuation amplitudes remained similar. The cross-phase between potential and density fluctuations varies with increasing mirror ratio, suggesting a shift in the underlying linear instability as the mirror ratio is increased and magnetic curvature is introduced. Changes in energy confinement, zonal flows, and turbulence as a function of mirror ratio will be presented.