Accession Number : ADA186407

Title :   Laser Thermal Propulsion.

Descriptive Note : Final rept. 1 Jan 83-31 Aug 86,

Corporate Author : TENNESSEE UNIV SPACE INST TULLAHOMA

Personal Author(s) : Keefer, Dennis

PDF Url : ADA186407

Report Date : 05 Jun 1987

Pagination or Media Count : 9

Abstract : The objective of this research investigation was to determine, experimentally and analytically, the physical mechanisms that control the behavior of continuous, laser sustained plasmas. The principle questions involve the effects of a forced convection environment and optical geometry on the stability, fractional power absorption, plasma structure, and fluid mixing. A continuous, 1.5 kW, axial flow, carbon dioxide laser was used to create the LSP in a cylindrical quartz flow channel. The convection flowfield surrounding the plasma was controlled by the volume flow through the test chamber, and the optical geometry was determined by the unstable oscillator output mode of the laser and the focal length of the lens. Digital images of the plasma in a selected narrow wavelength interval were obtained using a CID digital camera and a VICOM digital image processing computer that were calibrated for absolute radiance. These images were then Abel inverted to give a spatial plasma emission coefficient which determined the spatial distribution of the plasma temperature. These measured temperature fields were then used to calculate the laser power absorption in the plasma and the power lost from the plasma through optically thin emission. More than one hundred sets of data were obtained for argon plasmas at nominal pressures from 1.5 to 3 atmospheres and incident flow velocities from 0.4 to 4.0 m/s.

Descriptors :   *THERMAL PROPULSION SYSTEMS, *LASER APPLICATIONS, ABSORPTION, ARGON, AXIAL FLOW, CARBON DIOXIDE LASERS, CHAMBERS, CHANNELS, COEFFICIENTS, CONVECTION, CYLINDRICAL BODIES, DIGITAL COMPUTERS, DIGITAL SYSTEMS, EMISSION, FLOW, FLOW FIELDS, FLUIDS, FREQUENCY, GEOMETRY, IMAGE PROCESSING, IMAGES, INTERVALS, LASERS, LENGTH, MIXING, OPTICAL PROPERTIES, OSCILLATORS, OUTPUT, PLASMAS(PHYSICS), POWER, QUARTZ, RADIANCE, SPATIAL DISTRIBUTION, TEMPERATURE, TEST FACILITIES, VELOCITY, VOLUME, EMISSION SPECTROSCOPY

Subject Categories : Electric and Ion Propulsion
      Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE