A Plasma Initiation/Flow Chamber to Study CW Laser Beamed Energy Absorption in Light Gases

This report summarizes the research work that has been done in the past year, investigating the use of laser-sustained plasmas for propulsion applications. One focus of the research is the initiation of plasmas in inert gases using metal vapor seedants. Another is to define the operating characteristics of the dual-flow design by measuring temperatures, number densities, and global absorption. A pressure chamber has been built to permit observations of the plasma under wide ranges of pressure, flow conditions, and beam geometry. Laser energy absorption will be measured using a high -flux calorimeter, and temperature profiles will be found using a combination of spectroscopic relative line intensity measurements, thermocouples, infrared thermography, and possible laser induced fluorescence. The report summarizes the design and construction of the pressure chamber, optics, and related equipment, and discusses the techniques which will be used to analyze temperatures throughout the flowfield. Keywords include: Beam energy propulsion, CW laser application, Absorption of electromagnetic radiation.