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The micro-impulse generated by ablating aluminum target in double-pulse laser bursts with different interpulse delays was investigated using the torsion pendulum. The plasma plume was simultaneously visualized using high-speed photography to analyze the coupling mechanism of the ablation impulse. The experiment was carried out using the pulsed laser with the pulse width of 8 ns and the wavelength of 1064 nm. The experimental results show that the impulse with an interpulse delay of 60 ns is roughly 60% higher compared to that with no delay between the two pulses when the energy of both laser pulses is 50 mJ. Therefore, the double-pulse schemes could enhance the ablation impulse under certain conditions. The reason is that the ablation of the first laser pulse changes the optical properties of the aluminum target surface increasing the absorptivity. However, the ablation impulse is reduced at the time delay of 20 ns when the energy of both laser pulses is 100 mJ or 150 mJ. It can be concluded that the plasma produced by ablating aluminum of the first pulse shields the second laser pulse. To summarize, the experimental results show that different delay time in double-pulse scheme has a significant effect on the ablation impulse. The study provides a reference for the optimization of the parameters when the laser ablation propulsion with double-pulse scheme is applied in the fields of space debris removal, laser ablation thruster, and so on.

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