Development of truly noninvasive ultrafast imaging diagnostics and advanced plasma flow solver for fundamental studies of low-temperature, non-equilibrium plasmas

The U.S. Department of Energy has determined that a need exists to develop a more fundamental and detailed understanding of the basic physics and chemistry of low temperature plasmas (LTP) ( & lt;10 eV). These non-equilibrium LTPs have a multitude of applications ranging from semiconductor manufacturing, lighting and displays, material science, propulsion as well as biology and medicine. Developing an experimental, theoretical, and model-based predictive capability is crucial for enhancing our understanding of LTP and subsequent transformation into technologies and products with high potential return on investment. This proposal, developed by Spectral Energies, LLC (SE) in collaboration with the Ohio State University Non-Equilibrium Thermodynamics Laboratory (OSU-NETL), offers a package containing advanced truly noninvasive plasma diagnostics tools and computational flow solver. The SEOSU team has over fifty years of combined experience in this research area. Current state-of-the-art, laser-spectroscopy-based plasma diagnostic tools are often plagued by laser-induced photochemistry, limited spatial dimensionality and slow data acquisition rates. The scientists at SE have recently developedfor the first timefemtosecond-laser-based, high-bandwidth (1-10 kHz) imaging techniques for combustion diagnostics, which include collision-free 1-D thermometry and photolytic-interference-free 2-D imaging of key reaction intermediates. We offer to integrate such advanced diagnostics tools to develop and validate a comprehensive plasma code for measuring/predicting essential LTP properties and multi-dimensional structures. The objectives of the proposed program are: (i) The development of photolytic-interference-free, quantitative 2-D imaging of critical atomic species of O, N, and H using femtosecond two photon laser induced fluorescence (fs-TPLIF) technique; (ii) The development of 1-D imaging of electric field distribution, and rotational/translational temperature and vibrational distribution function, using fs coherent Anti-Stokes Raman scattering (fs-CARS) spectroscopy; (iii) the development of a 2-D Master Equation plasma flow solver, which enhances existing 2D plasma codes by incorporating an extensive set of internal energy state (vibration, electronic) specific kinetic processes and rates; and (iv) a set of comprehensive studies of LTP using integrated diagnostic-computational methods developed above. Elements (i)-(iii) will be demonstrated during Phase I using existing optically accessible, nanosecond pulsed plasma test chambers. Following necessary refinements, the theoretical code developed will be compared with detailed experimental measurements (Element iv) for a chosen set of plasma conditions during Phase II. The unique integrated diagnosticcomputational framework developed will generate an array of new marketable products and technologies for LTP applications.