Optical Ion Velocity Diagnostics in the Interaction of a Laser Produced Plasma and an Ambient Magnetized Plasma

Measuring particle velocities is crucial to understanding plasma dynamics in the study of diamagnetic cavity formation, anomalous magnetic diffusion, plasma instabilities, and collisionless shock formation and dynamics. We present two methods of measuring super-Alfvénic debris particle properties of a laser-produced plasma (LPP). The first uses a high temporal and spectral resolution monochromator coupled to a photomultiplier tube (PMT) to measure fluorescence from debris and ambient ions to determine velocity distributions by charge state in a field parallel geometry. Fluorescence traces were time-integrated post-experiment to conduct a low resolution spectroscopic survey from 185-680 nm. The resulting spectra can be compared to NIST and collisional-radiative model data in order to evaluate the population densities and temperatures of the various species in our plasma.

Additionally, we propose an innovative application of planar laser induced fluorescence (PLIF) on an expanding, super- Alfvénic LPP. PLIF is a widely used, noninvasive optical technique that can determine ion distributions, velocities, and qualitative concentrations with a high degree of spatial and temporal resolution. By using collisional-radiative simulations, we have identified the configurations in which the best signal to noise ratio (SNR) will be obtained. Hybrid simulation results are displayed to help visualize the expected results.