Small-Scale, Shear-Driven Irregularities and Associated Particle Heating

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The objective of the proposal is to utilize laboratory plasma experiments to identify the physics and characterize the signatures of space-relevant fluctuations, small-scale irregularities, and particle heating induced by velocity-shear driven mechanisms. In particular, the project will attempt to, 1.) determine the dependence of Kelvin-Helmholz, inhomogeneous energy-density driven, and electron-ion hybrid Kelvin-Helmholtz excitation thresholds on shear parameters, 2.) test the ability to seed shear-driven turbulence at the edges of nonlinearly evolved Kelvin-Helmholtz vortices in plasma potential, 3.) distinguish the ion heating induced by different shear-driven waves from that resulting from current-driven waves, and 4.) determine the influence of introducing small concentrations of a second positive-ion species on items 1-3 above. The specific long range goals are to improve the interpretation of the dynamically intense geomagnetic activity that arises at the edges of auroral arcs and in black aurora and to provide quantitative comparisons to theoretical models used to interpret space observations.