Laser propulsion using a molecular absorber Conference Paper uri icon

abstract

  • © 1998 by Princeton University. Unlike the conventional approach of using a laser sustained plasma to heat a propellant, molecular absorption of laser energy makes it possible to avoid the frozen flow losses associated with the high temperature and complex chemistry of a plasma. The molecular absorption concept is developed by exploring several thermodynamic pathways using a 1-D fluid theory for energy addition in the supersonic regime and different pathways are shown in H-K coordinates. The absorption physics of a promising molecular absorber, SF6, is described at arbitrary laser beam intensities using a two-temperature non-equilibrium model, which is then applied to calculate the nozzle length required to achieve a specific impulse of 250 sec through a 300 K isothermal expansion in the supersonic section. The results of this conversative example case for energy addition illustrate that over a length of less than 1 m laser power on the order of 20 kW can be absorbed in the supersonic region of a 10 g/sec H2 flow without creating a plasma.

author list (cited authors)

  • Chiravalle, V., Miles, R., & Choueiri, E.

citation count

  • 2

publication date

  • January 1998
  • January 1, 1998 11:11 AM