电磁波在等离子体高温气体中传输特性实验研究

针对高超声速飞行器头身部形成的等离子体鞘套对通信的影响,在中国空气动力研究与发展中心的粉末激波管上开展了电磁波在等离子体高温气体中传输特性的实验研究。实验中获得了等离子体气体中的电磁波透射率、电子密度和碰撞频率。实验结果表明：X波段和Ka波段电磁波在高激波马赫数Mas=16.1、1区气体压力P1=1200Pa的激波管实验状态下产生的厚度80mm等离子体高温气体中能量衰减大于30dB,难以传输;X和Ka波段电磁波在激波马赫数Mas=15.9、1区气体压力P1=80Pa的激波管实验状态下产生的厚度80mm等离子体高温气体中能量衰减大于30dB,难以传输;X波段和Ka波段电磁波在激波马赫数Mas=10.1、1区气体压力P1=80Pa的激波管实验状态下产生的高温等离子气体中平均传输损耗较小,可以进行有效传输;Ka波段电磁波在激波马赫数Mas=8.9、1区气体压力P1=1200Pa的激波管实验状态下产生的厚度80mm等离子体气体中平均传输损耗小于1dB,可以进行有效传输。实验得到的等离子体高温气体中的电磁波透射率、电子密度和碰撞频率与理论计算值基本一致。

Experimental investigation on electromagnetic wave transmission characteristic in the plasma high temperature gas

In order to study the influence of plasma sheath on communication,the experimental investigation of electromagnetic wave（EMW） transmission characteristic in the plasma high temperature gas has been carried out at shock tube.The EMW transmittivity,electron density,and electron-neutral collision frequency in the plasma gas have been obtained.The results show that neither X band EMW nor Ka band EMW can be propagated in the plasma gas generated under the conditions of high shock Mach number Mas=16.1 and domain 1 gas pressure P1=1200Pa.Also,neither X band EMW nor Ka band EMW can be propagated in the plasma gas generated under the conditions of shock Mach number Mas=15.9 and domain 1 gas pressure P1=80Pa.Both X band EMW and Ka band EMW can be transmitted with small attenuation in the plasma gas generated under the conditions of shock Mach number Mas=10.1 and domain 1 gas pressure P1=80Pa.In addition,the Ka band EMW can be transmitted with small attenuation in the plasma gas generated under the conditions of shock Mach number Mas=8.9 and domain 1 gas pressure P1=1200Pa.The experimental results on the EMW transmittivity,electron density,and collision frequency in the plasma gas are in agreement with the calculational ones.