Laser plasma propulsion in glass-layer confined ablation was experimentally investigated. The results showed that compared to that of direct ablation, the coupling coefficient was enhanced over ten times. By observing...Laser plasma propulsion in glass-layer confined ablation was experimentally investigated. The results showed that compared to that of direct ablation, the coupling coefficient was enhanced over ten times. By observing the plasma expansion and calculating the ablation pressure, it was found that a higher ablation pressure and larger glass mass resulted in a higher coupling coefficient in the confined laser ablation.展开更多
Laser propulsion is a new concept technique of propulsion and will have important application in future space technology. There are two main driving types: the air-breathing mode and the rocket ablation mode. Vertical...Laser propulsion is a new concept technique of propulsion and will have important application in future space technology. There are two main driving types: the air-breathing mode and the rocket ablation mode. Vertical flight experiments have been carried out with a simple paraboloid type lightcraft in the air-breathing mode by TEA-CO_2 laser. In simulation a new model is used for LSD/LSC wave, the result shows that the momentum coupling coefficient increases with the increase of the pulse energy.展开更多
Energy law of similitude for laser propulsion refers to the law that there is an optimum nozzle configuration for the largest value of impulse coupling coefficient at certain incident laser energy. A dimensionless fac...Energy law of similitude for laser propulsion refers to the law that there is an optimum nozzle configuration for the largest value of impulse coupling coefficient at certain incident laser energy. A dimensionless factor combined with incident laser energy, nozzle configuration parameters and working gas parameters is introduced. Energy law of similitude is established by means of theoretical analysis, experimental study and numerical simulation of radiation gas-dynamics. The qualitative results obtained from theoretical analysis are verified by experimental and numerical results. Physical meaning and engineering application of dimensionless factor and energy law of similitude are analyzed. Results indicate that ① impulse coupling coefficient has a maximurn value with dimensionless factor of about 0.4; ② impulse coupling coefficient is independent of incident laser energy when dimensionless factor is constant. Conclusions and recognitions acquired in this article can not only present optimum nozzle configurations for the present laser energy level, but also provide a good guide for the optimum nozzle configuration design once the laser energy is amplified to a high level.展开更多
为研究飞秒脉冲激光冲击强化中等离子体压力时空演化规律,利用考虑电子态密度(DOS)效应的模型计算了电子热容和电声耦合系数随电子温度的演化规律,并与采用QEOS(quotidian equation of state)模型计算结果进行了对比;提出DOS飞秒脉冲激...为研究飞秒脉冲激光冲击强化中等离子体压力时空演化规律,利用考虑电子态密度(DOS)效应的模型计算了电子热容和电声耦合系数随电子温度的演化规律,并与采用QEOS(quotidian equation of state)模型计算结果进行了对比;提出DOS飞秒脉冲激光冲击强化模型,计算得到电子温度、晶格温度、等离子体羽位置时间演化规律和等离子体压力时空演化规律,并与QEOS飞秒脉冲激光冲击强化模型结果进行了对比。结果表明:DOS飞秒脉冲激光冲击强化模型计算得到的等离子体羽位置随时间的演化规律与实验结果吻合程度更好;增加激光能量或功率密度、考虑电子DOS效应会增加电子、晶格温度和等离子体压力。展开更多
基金National Natural Science Foundation of China(Nos.10334110,10510490 and 10675164)
文摘Laser plasma propulsion in glass-layer confined ablation was experimentally investigated. The results showed that compared to that of direct ablation, the coupling coefficient was enhanced over ten times. By observing the plasma expansion and calculating the ablation pressure, it was found that a higher ablation pressure and larger glass mass resulted in a higher coupling coefficient in the confined laser ablation.
文摘Laser propulsion is a new concept technique of propulsion and will have important application in future space technology. There are two main driving types: the air-breathing mode and the rocket ablation mode. Vertical flight experiments have been carried out with a simple paraboloid type lightcraft in the air-breathing mode by TEA-CO_2 laser. In simulation a new model is used for LSD/LSC wave, the result shows that the momentum coupling coefficient increases with the increase of the pulse energy.
基金National Natural Science Foundation of China （ 10672184） National Basic Research Program of China （61328）
文摘Energy law of similitude for laser propulsion refers to the law that there is an optimum nozzle configuration for the largest value of impulse coupling coefficient at certain incident laser energy. A dimensionless factor combined with incident laser energy, nozzle configuration parameters and working gas parameters is introduced. Energy law of similitude is established by means of theoretical analysis, experimental study and numerical simulation of radiation gas-dynamics. The qualitative results obtained from theoretical analysis are verified by experimental and numerical results. Physical meaning and engineering application of dimensionless factor and energy law of similitude are analyzed. Results indicate that ① impulse coupling coefficient has a maximurn value with dimensionless factor of about 0.4; ② impulse coupling coefficient is independent of incident laser energy when dimensionless factor is constant. Conclusions and recognitions acquired in this article can not only present optimum nozzle configurations for the present laser energy level, but also provide a good guide for the optimum nozzle configuration design once the laser energy is amplified to a high level.
文摘为研究飞秒脉冲激光冲击强化中等离子体压力时空演化规律,利用考虑电子态密度(DOS)效应的模型计算了电子热容和电声耦合系数随电子温度的演化规律,并与采用QEOS(quotidian equation of state)模型计算结果进行了对比;提出DOS飞秒脉冲激光冲击强化模型,计算得到电子温度、晶格温度、等离子体羽位置时间演化规律和等离子体压力时空演化规律,并与QEOS飞秒脉冲激光冲击强化模型结果进行了对比。结果表明:DOS飞秒脉冲激光冲击强化模型计算得到的等离子体羽位置随时间的演化规律与实验结果吻合程度更好;增加激光能量或功率密度、考虑电子DOS效应会增加电子、晶格温度和等离子体压力。
