Experimental Investigation of Air-breathing Mode of Laser Propulsion with Elongate Cylindrical Models and CO2 Lasers of Different Pulse Durations

The experiments on laser propulsion of cylindrical models with spherical forebodies have been reported. The models with masses 2-5 g were propelled by a TEA CO2 laser (7 J, I ms, 30 Hz). The coupling coefficient C. increased with cylinder length L. At nozzle diameter 20 mm it amounted to 50 dyne/W at L=60 mm and fluence 1=1.5 J/cm2. The wire-assisted flight with acceleration 18 m/s2 was demonstrated for 3.3 g-model 60 mm-long. The same model was tested in experiments with a single-pulse e-beam-sustained CO2 laser (30 J, 10-24 ps). It was shown that momentum transferred to the model increases with I regardless of pulse duration c if the breakdown threshold is exceeded. The maximum Cmm~70 dyne/W was demonstrated for 3.3 g-model at t=10 ms and I = 3 J/em2. Cm~60 dyne/W was obtained for a 140 g-model with a single-pulse TEA CO2 laser (125 J, I ms).