Development of MegaHertz Laser-Induced Fluorescence for Visualization of Turbulence

60174 Turbulence is a key factor in the performance of fusion experimental devices, but is poorly understood. The visualization of turbulent processes is an important tool in understanding the phenomenon. In this project, a high repetition rate MegaHertz tunable Alexandrite laser will be used to excite an ion emission line in a plasma. The resulting laser-induced fluorescence (LIF) will be imaged onto an ultra-fast imaging detector to reveal the temporal evolution of turbulent structures in the plasma with high spatial resolution. In Phase I, several ions were investigated to determine the optimal species for laser-induced fluorescence visualization. The MegaHertz Alexandrite laser was designed, based on the laser energy required for the selected ion species. The expected signal and signal-to-noise were estimated based on a proposed experimental setup. In Phase II, after delivery of the ultra-fast CCD camera and MegaHertz burst Alexandrite laser, a proof of principle experiment will be implemented. This will be done on the Magnetic Reconnection Experiment (MRX) at the Princeton Plasma Physics Laboratory. Commercial Applications and Other Benefits as described by the awardee: Turbulence plays an important role in aerodynamics, combustion, and many other physical processes. Laser-induced fluorescence imaging also could be applied in the commercial sector to aid in environmental monitoring, plasma processing of semiconductors, and medical diagnostics.