序列脉冲激光在不同大气模型下的热晕效应研究

考虑到大气中吸收系数随高度变化，通过内插法得到不同大气模型一定高度下大气的吸收系数，建立序列脉冲激光在地对空垂直传输的热晕模型。通过数值计算方法分析风场渡越时间内脉冲数为2时的序列脉冲在中纬度地区夏季和冬季、热带地区、近北极地区夏季和冬季5种大气模型下的热晕效应。结果表明:当光束孔径为0.25 m，初始功率为200 kW，波形为高斯状的激光束在近北极冬季传输10 km后沿横轴方向光强峰值偏移0.056 9 m，而热带光强峰值强度偏移最远为0.224 m，为近北极冬季时的4倍；脉冲激光在热带传输10 km后的靶面功率仅为15.06 kW，近北极冬季靶面功率为热带的10.5倍。热带地区的热晕效应最明显，中纬度地区次之，近北极地区最弱。激光在夏季传输要比冬季传输的热晕效应严重，而且近北极地区夏季要比中纬度地区冬季的热晕效应更严重。

Thermal blooming of repetitively pulsed laser propagation in different atmospheric models

Considering the variety of absorption coefficient along with different altitudes in different climates, this paper gets the absorption coefficient in a certain altitude by interpolation, sets up the model of transient thermal blooming of collimated repetitively pulsed laser from ground to air, and analyzes the transient thermal blooming by four-dimensional computer code. What is more, the paper simulates the model in 5 atmospheric models and simulates thermal blooming of continuous wave numerically. The results are as follows: In the same condition, after the laser transmits 10 km, in the region close to the North Pole, the nearest motion of the peak at the horizontal axis is 0.0569m in winter; the farthest motion of the peak at the horizontal axis is 0.224m in tropic. In the region close to the North Pole, the power in winter is 10.5 times as many as the power in tropic. Thermal blooming in tropic is more serious than that in mid-latitude region; thermal blooming in mid-latitude region is more severe than that in the region close to North Pole in the same season; thermal blooming in summer is more serious than that in winter in the same region; thermal blooming in summer in the region close to North Pole is more severe than that in winter in mid-latitude region.