电磁脉冲在地表大气中的传播

Propagation of Electromagnetic Pulses in the Earth Surface Atmosphere

利用传递函数的方法研究电磁脉冲在大气中的传播规律 ,通过数值计算比较了矩形脉冲在实际地表大气和真空中衰减的差别 ,对矩形脉冲和正弦波 ,不同上升、下降沿梯形脉冲的大气衰减特性也做了比较。数值结果表明 ,大气吸收衰减使脉冲传播的距离降低 ,由于大气对不同频率电磁波的吸收不一致 ,矩形脉冲、正弦波在大气中的衰减随距离交迭变化 ,具有不同频谱分布的脉冲在大气中传播也有差异。

The propagation of electromagnetic (EM) pulse in air is studied by using the method of transfer function. Some attenuation differences in atmosphere and vacuum for square pulse are compared. The atmosphere attenuation for square pulses, sinusoidal pulses, and trapezium pulses with different slope rising and undershoot falling edges are given. The numerical results show that atmosphere absorbing attenuation shortens the propagation distance of the pulses. Since the atmosphere absorbs EM waves for different frequency with different rate, the attenuation of square pulses and sinusoidal waves are changed alternatively with distance. The propagation is different for the pulses with different spectrum distribution in the atmosphere.