Femtosecond TALIF Imaging of Atomic Hydrogen in Pulsed, Non-Equilibrium Plasmas

Abstract

In recent decades significant interest has been paid to investigate the applications of non-equilibrium plasma discharges to a variety of practical combustion related applications. However in order to develop a more fundamental understanding of such phenomena, additional insight into important kinetic processes is of great importance. A two-photon absorption laser-induced fluorescence (TALIF) technique is developed utilizing wide-bandwidth, short-time duration, femtosecond (fs) laser pulses. Due to its increased bandwidth and short pulse duration, fs-TALIF has reduced impact from photo-dissociation and increased signal compared to traditional nanosecond TALIF schemes. This fs-TALIF technique is used to image key atomic species within nanosecond pulsed, non-equilibrium discharges at moderate pressures. These two dimensional results provides both spatial and temporal information that can be used in more predictive plasma kinetics models. 1 Research Engineer, Spectral Energies, LLC., 5100 Springfield St, Suite 301, Dayton, OH 45431, AIAA Member 2 Senior Research Scientist, Spectral Energies, LLC., 5100 Springfield St, Suite 301, Dayton, OH 45431, AIAA Associate Fellow 3 Senior Research Scientist & CEO, Spectral Energies, LLC., 5100 Springfield St, Suite 301, Dayton, OH 45431, AIAA Associate Fellow 4 Research Associate, The Ohio State University, Columbus, OH 43210, AIAA Member 5 Professor, The Ohio State University, Columbus, OH 43210, AIAA Associate Fellow 6 Principal Research Chemist, Air Force Research Laboratory, WPAFB, OH 45433, AIAA Associate Fellow