Study On Two Shock Waves Of Laser Plasma Propulsion

Laser plasma propulsion is the strategic commanding point for the future of aerospace,compared with the traditional chemical combustion propulsion and nuclear propulsion,laser plasma propulsion has potential advantages in terms of thrust,payload and stroke.Laser plasma propulsion uses strong laser irradiated propellants to produce high-temperature,high-pressure,high-density plasma,after a specially designed vent sprayed in a certain direction,to produce a huge thrust to promote the movement of the aircraft.The research on propulsion efficiency has always been the focus of laser propulsion technology,and based on the existing research results,the shock waves induced by laser plasma play a very important role in the process of propulsion,and the shock waves promote the propulsion process in the process of generating,propagation and decaying to sound waves.In addition,a second shock wave formed by reflection accelerates propagation in a heated medium of propagation,and if a shock wave is caught and interferes for a long time,then the laser plasma propulsion efficiency will be greatly improved,laser plasma shock wave propulsion will also move to a new stage.Based on the theory of laser plasma and shock wave,this paper first models the ablation pressure,ablation velocity,relaxation time and equivalent ablation depth in the process of generating plasma from the laser target;Secondly,the morphological parameters and volume of laser carbon plasma are studied theoretically and experimentally;Third,by establishing a one-dimensional model of laser plasma-induced shock waves,the process parameters of one shock wave and two shock waves are calculated and compared with the measurement data;Finally,based on the experimental principle of shock wave detection,the laser plasma shock wave propulsion cavity is designed,and the shock wave detection is carried out.The results show that:(1)the analog volume of laser carbon plasma expands rapidly with the increase of laser power density;(2)The measurement volume of plasma produced by the laser ablation carbon target is very different from the analog value;(3)In the case of transparent constraint layer,the propulsion effect of laser carbon plasma is significantly better than that of non-transparent constraint layer;(4)The amount of carbon ablation produced by the laser ablation carbon target on the transparent restraint layer increases with the increase of the laser power density;(5)The simulation parameters of one shock wave and two shock waves of laser plasma are basically consistent with the measurement data reported in the literature;(6)One shock wave and two shock waves are detected in the designed laser plasma shock wave propulsion chamber.Four conclusions can be drawn from this: First,it is shown that the one-dimensional model of plasma produced by laser ablation carbon target is correct,the steps of binding electrons to occupy the probability equation system and fluid mechanics equation system in the process of coupling and solving atomic physics are reliable,and the simulation results of laser plasma parameters are reasonable and can guide the relevant experimental operation;Second,in the case of the same laser power density,the transparent restraint layer has indeed played a role in promoting the laser plasma,and the carbon atom deposited on the transparent glass sheet means that the amount of ablation increases with the increase of the laser’s power density;Third,the measurement data of the shock wave provided by the literature verify that the analog parameters of the laser plasma shock wave are reliable;Fourth,based on the detection principle of laser plasma shock wave,one shock wave and two shock waves are detected from the designed shock wave propulsion chamber.Laser plasma shock wave propulsion is not only related to structural parameters such as cavity type and target material,but also to physical parameters such as laser power density,plasma parameters and shock wave sources.Although the coherent propulsion of laser plasma shock waves is not realized,these results provide a meaningful reference for further study of laser plasma shock wave propulsion.