Development of laser diagnostics on a two-terawatt pulsed power accelerator.

摘要

An interferometric laser optical diagnostic was developed to analyze plasma behavior and properties in Magnetically Insulated Transmission Lines (MITL) and other high energy density experiments. The diagnostic produces interferograms needing to be analyzed to achieve quantitative data from experiments. Research focused on analyzing interferograms by using Quick Fringe, a commercial software package, showing the plasma density field in experimental interferograms. Issues in analysis included benchmarking Quick Fringe, exploration of vibration effects on reference interferograms used to retrieve data from interferograms containing data, and revealing program limitations. Benchmarking of Quick Fringe shows that interferograms of a lens could be analyzed successfully by utilizing various methods to calculate the lens geometry within +/-0.05 waves. Vibration issues were mitigated by either creating a reference interferogram, or averaging multiple reference interferograms. Quick Fringe calculated the results of the MITL interferogram to have a maximum fringe shift to be ∼0.5 to ∼0.7 waves, which correlates to a plasma density of >2--3 · 1016 cm-3.