Target momentum measurement in laser plasma propulsion using two probe beams

A new method to measure the target velocity in laser plasma propulsion is proposed. By this method, the target velocity can be directly measured. The target thickness and the probe beam have no effects on measurement results. Compared with theoretical result, the error of experimental result is less than 2%. Furthermore, using this method, target momentum generation in laser-ablation water under different ambient temperatures is measured. Results show that the target momentum increases as the temperature decreases.