Temporally Resolved Ion Fluorescence Measurement of the Interaction of a Field-Parallel Laser Produced Plasma and an Ambient Magnetized Plasma

We present measurements of a super-Alfvenic debris velocity distribution of a laser-produced plasma (LPP) using a high temporal and spectral resolution monochromator. The LPP was created by focusing one of two high energy lasers onto a high density polyethylene (HDPE) target embedded in the ambient magnetized plasma of the Large Plasma Device (LAPD) at the University of California, Los Angeles. The resulting ablated debris ions interact with the background magnetic field (300 G) through electromagnetic instabilities over 12 m, equivalent to 80 ion inertial lengths (δi ), of the LAPD. The monochromator measures fluorescence from debris and ambient ions to determine the debris velocity distribution by charge state. Monochromator time traces were integrated post-experiment to conduct a low resolution spectroscopic survey from 185-680 nm. This is compared to NIST spectral data in order to evaluate the relative populations of elements and charge states in the ambient plasma and LPP. Results are discussed in the context of laboratory laser-driven electromagnetic instability growth.