电磁波在非磁化等离子体中衰减效应的实验研究

针对等离子体隐身技术在航空航天领域的良好应用前景, 开展垂直入射到具有金属衬底的非磁化等离子体中电磁波衰减特性的理论与实验研究. 利用WKB方法对电磁波衰减随等离子体参数的变化规律进行了理论分析. 利用射频电感耦合放电方式产生稳定的大面积等离子体层, 搭建了等离子体反射率弓形测试系统, 进行了电磁波在非磁化等离子体中衰减效应的实验研究. 利用微波相位法和光谱诊断法, 得到不同放电功率下的等离子体电子密度, 其范围为8.17×10⁹–7.61× 10¹⁰ cm^-3. 本实验获得的等离子体可以使2.7 GHz 和10.1 GHz电磁波分别得到一定的衰减, 且电磁波衰减的理论与实验结果符合较好. 结果表明, 提高等离子体电子密度和覆盖均匀性有利于增强等离子体对电磁波的衰减效果.

Experimental investigation on attenuation effects of electromagnetic waves in an unmagnetized plasma

Plasma stealth technology has many unique advantages, hence it has a promising application in the aviation and aerospace fields. The attenuation characteristics of vertical incidence of electromagnetic waves into unmagnetized plasmas with metal underlay are studied theoretically and experimentally in this paper. Regulations for the change of electromagnetic wave attenuation with plasma parameters are analyzed in theory using WKB method. A-large-area plasma slab is generated stably by inductively coupled discharge, and the reflectivity arch test system of plasma slab is set up. While the attenuation effects of electromagnetic wave in unmagnetized plasmas are studied experimentally. The electron density of plasma generated at different discharge powers is obtained by using the microwave phase and plasma spectrum diagnostic technique, ranging from 8.17× 10⁹ to 7.61× 10¹⁰ cm^-3. The plasma generated by inductively coupled plasma (ICP) has an effect on the attenuation of electromagnetic waves, and the experimental results accord well with the theoretical ones. Results show that increasing the plasma electron density and covering homogeneity can contribute to improving the attenuation effect of plasma on electromagnetic waves.