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 experi-mental 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.