Effects of conical nozzle configuration on impulse coupling coefficient in repetitively-pulsed laser propulsion

A dimensionless factor was introduced to deduce the analytic expression of impulse coupling coefficient for conical nozzles in the case of spherical symmetry, and a high precision impact pendulum system was used to measure impulse coupling coefficients of 15 conical nozzles with different cone angles and lengths. The expression was corrected according to experimental values. The results indicate that: 1) impulse coupling coefficient increases firstly and then decreases with augment of dimensionless length when cone angle is fixed; 2) impulse coupling coefficient decreases monotonously with augment of cone angle when dimensionless length is fixed; 3) it is of great importance for improving impulse coupling coefficient to increase the rate of laser energy deposition.