Accession Number:

ADA158273

Title:

Experimental and Theoretical Studies of Laser Propulsion Phenomenology.

Descriptive Note:

Final technical rept. 15 Jan 84-28 Feb 85,

Corporate Author:

PHYSICAL SCIENCES INC ANDOVER MA

Report Date:

1985-03-01

Pagination or Media Count:

37.0

Abstract:

The work performed in this 2-year effort involved two tasks one dealing with issues related to laser energy absorption in a pulsed thruster and the other dealing with issues related to laser energy absorption in a CW thruster. For the pulsed studies, the first years effort involved theoretical and experimental investigations of the threshold requirements for achieving laser-induced gas breakdown at short wavelengths 1 micrometer. With these breakdown studies completed, the next step, initiated in the second year, was to determine the degree of pulsed laser energy absorption that can be achieved in the laser-initiated plasma. Toward this end pulsed laser energy deposition studies were performed using a pulsed Ndglss laser as the energy source wavelength 1.05 micrometers, pulse duration 20 ns and high pressure hydrogen and argon gases as the absorption media. The percentage of laser energy absorbed in the laser-produced plasma was determined from measurements of the fraction of laser energy transmitted through the breakdown region as well as from optical interferometric measurements to determine the strength of the laser-produced blast wave. The initially deposited energy was inferred from the measured blast wave trajectories by comparing them with predicted trajectories calculated by a detailed hydrodynamic model. Results are presented for the energy deposition efficiency achieved in argon and hydrogen as a function of initial gas pressure 0.3 atm P 10 atm.

Subject Categories:

  • Lasers and Masers

Distribution Statement:

APPROVED FOR PUBLIC RELEASE