Feasibility studies of two-dimensional edge turbulence measurements by laser induced fluorescence

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Abstract
Edge turbulence is a key factor in the performance of fusion devices but is not well understood even after many years of research. We assess the feasibility of using laser induced fluorescence to obtain two-dimensional images of turbulent structures in the plasma. Based on theoretical expectations of density fluctuations arising from turbulence and calculations of level populations in He-like and noble gas ions we show that high signal/noise ratios ( S/N >100) may be expected for experimental conditions in the magnetic reconnection experiment and on the National Spherical Torus Experiment at PPPL. Schemes include exciting the ion emission lines such as B IV 282.3 nm or Kr II 441.8 nm by a tunable laser.