Speaker
Dr
Sean Kearney
(Spectral Energies LLC/Air Force Research Laboratory)
Description
Plasmas and reacting flows are essential in a wide array of defense, commercial, space, energy, medical, and consumer-product applications. Understanding the complex physical and chemical characteristics of such systems requires measurements of key parameters, including temperature, pressure, electric field, velocity, and number densities of chemical species. Time-resolved measurements of key chemical species and temperature are required to explore reaction kinetics and transient phenomena. Laser-based, noninvasive linear and nonlinear spectroscopic approaches have proven to be extremely valuable for providing key insights into the physicochemical processes governing plasmas and reacting flows as well as validating numerical models. The advent of kHz-rate amplified femtosecond lasers has enabled multidimensional imaging of key atomic species such as H, O, and N, providing unprecedented insights into preferential diffusion and production of these species through chemical reactions and electric-field-driven processes. These lasers not only provide two-dimensional imaging of chemical species but also have the ability to perform measurements free of various interferences. Moreover, these lasers allow one and two-dimensional temperature-field measurements which were unimaginable only a few years ago. The rapid growth of ultrashort-pulse spectroscopy and imaging has been fueled by the need to achieve 1) interference-free measurements (collisional broadening, Stark broadening, photolytic dissociation, etc.); 2) time-resolved single-shot measurements at kHz rates; 3) spatially resolved measurements; 4) increased dimensionality (point, linear, planar, volumetric); and 5) simultaneous measurements of multiple species and flow parameters. This lecture will address continuing efforts to achieve these goals through the application of emerging ultrashort-pulse laser technologies.
Primary author
Dr
James Gord
(Air Force Research Laboratory)
Co-author
Dr
Sean Kearney
(Spectral Energies LLC/Air Force Research Laboratory)
