A proposed method for the measurement of multi-pulse thrust produced by a laser thruster with a polyvinylidene fluoride (PVDF) sensor

A system for testing the thrust loading process of a laser produced multipulse using a polyvinylidene fluoride (PVDF) sensor has been developed and demonstrated. The effect of laser pulse frequency on the impulse coupling coefficient, C_m, in laser propulsion was studied by analysing the characteristics of experimentally derived thrust curves. The results showed that there was sufficient time for air to enter the work space when the frequency of laser pulse was 10 Hz or less. Clear interference of the first pulse on those following ones was evident with pulse frequencies of 25 Hz and above. At 25 Hz and beyond the C_m will decrease without an inlet channel due to the inability of sufficient air to enter the work space in the reduced time available between laser pulses and provide a propellant. The knowledge gained from this work will be very instructive for the future design of the inlet channels of a laser thruster.