Progress on development of optical tomography as a plasma diagnostic

Recent advances in laser diagnostics and models have been able to investigate well-controlled idealized plasmas in 2D fashion, but the spatially complex structure in actual plasmas requires a technique than can provide a more complete 3D picture. To address this limitation, a plasma tomographic optical imaging capability is being developed at Sandia National Labs. The system includes four intensified cameras that measure angular projections of the light source. An algebraic reconstruction technique (ART) is used to determine the light intensity at each voxel using the method of projections onto convex sets. Initial efforts will focus on 3-D optical emission spectroscopy. The primary development challenge includes achieving sufficient 3-D spatial and temporal resolution to resolve features of interest. A nanosecond pulsed atmospheric pressure plasma jet is investigated as an initial demonstration of the technique.