The velocity variation law of shock wave induced by millisecond-nanosecond combined-pulse laser has been investigated experimentally. The pulse delay and laser energy are important experimental variables. The method of laser shadowgraphy is used in the experiment. Experimental results show that when the pulse delay is 2.4 ms, the ms and ns laser energy density is 301 J cm⁻² and 12 J cm⁻², respectively, the velocity of shock wave is 1.09 times faster than that induced by single ns pulse laser. It is inferred that the shock wave propagates in the plasma is faster than that in air. When the ms and ns laser energy density is 414.58 and 24 J cm⁻², the velocity of shock wave shows rising trend with pulse delay in a range of 1.4 ms>Δt> 0.8 ms. It is indicated that with the increase of ns laser energy, the laser energy absorbed by laser-supported absorption wave increases. The mechanism of inverse bremsstrahlung absorption acts with target surface absorption simultaneously during the ns laser irradiation. Thus, the phenomenon of the double shock wave is induced. The numerical results of the phenomenon were accordance with experiment. The results of this research can provide a reference for the field of laser propulsion.

实验研究了毫秒-纳秒组合脉冲激光激波的速度变化规律。脉冲延迟和激光能量是重要的实验变量。实验采用激光阴影法。实验结果表明，当脉冲延迟为2.4 ms时，ms和ns激光能量密度分别为301 J cm ^-2和12 J cm ^-2，激波速度比单个ns脉冲产生的速度快1.09倍激光。据推测，激波在等离子体中的传播速度比在空气中快。当ms和ns激光能量密度为414.58和24 J cm ^{-2 时}，冲击波速度呈上升趋势，脉冲延迟在1.4 ms> Δt范围内> 0.8 毫秒。表明随着ns激光能量的增加，激光支持的吸收波吸收的激光能量增加。在 ns 激光照射期间，逆韧致辐射吸收的机制与目标表面吸收同时作用。这样，就产生了双激波现象。该现象的数值结果与实验相符。该研究结果可为激光推进领域提供参考。