Dynamic effects of aluminum target ablated by combined pulsed/continuous laser

The formation of expansion plume by pulsed laser irradiation on solid target material can generate reverse velocity impulse, which can be applied in the fields of space target propulsion and space debris removal. Compared with traditional singlelaser ablation, combined pulsed/continuous laser ablation has the characteristics of high ablation efficiency and low requirements for laser energy output. To investigate the dynamic characteristics of the expansion plume under the conditions of different laser action time and different laser spot sizes during combined laser ablation of target material, explore the evolution law of the expansion plume generated by combined laser ablation of target under different laser parameters, establish a dynamic response simulation model of combined laser ablation of target, and carry out research on the dynamic effects of combined laser ablation of target. The research results indicated that when pulsed laser act on the target material, the velocity of the expansion plume and the velocity of the target material increase with increasing energy; when the energy is 5J, the maximum expansion plume velocity is 1.15 10⁴ m/s. For the combined laser ablation, the target material velocity increases by 147% compared to single pulse laser when the continuous laser action time is 2000ms and the pulse laser energy is 10J. At the same time, under the same continuous laser interaction time (2000ms) with a pulsed laser energy of 10 J, the target velocity with a continuous laser spot radius of 0.5 cm is 129% higher than that with a spot radius of 1.5 cm. The optimal velocity enhancement effect on the target is achieved when the spot diameter ratio of the continuous laser to the pulsed laser is 1:1, indicating that spot size plays a critical role in optimizing target velocity. A comparative analysis of expansion plume generation and thrust effects between pulsed laser ablation and combined laser ablation demonstrates that combined laser ablation exhibits superior performance in both enhancing expansion plume velocity and boosting target velocity.