垂直入射电磁波在大气压非平衡等离子体层中的传播特性

Propagation characteristics of a vertical incident microwave in a non-equilibrium plasma slab at atmospheric pressure

用数值模拟的方法对大气压非平衡等离子体薄层中,不同的电子密度分布对微波反射、吸收和透射的影响进行了研究。所采用的理论分析方法是分层模型和镶嵌不变原理。计算中考虑了微波在子层间的多次反射和吸收。数值结果表明,对于电磁波的吸收来说,等离子体中具有二次分布的电子密度,其效果要高于线性分布10%左右;而对于反射来说,线性分布效率更高。功率反射系数随波长的增大而增大,功率吸收系数A也不是单调的,当电子密度不变时,A存在一个峰值,随着电磁波波长的增加而增加,达到最大值后,缓慢降低。

The effects of electron number density and its profile on the microwave propagation characteristics in a plasma slab are discussed. The incident wave travels vertically on the plasma slab. The plasma layer is modeled as adjacent, homogeneous sub-slaps, whose approximate distributions are linear or parabolic. The theoretical method to analyze the propagation of the wave is based on the stratified layer model and invariant imbedding principle. Multiple reflections between sub-slab interfaces are analyzed with the model. The numerical result shows that absorption with parabolic distribution plasma is better than the linear one, but the reflection is higher for the linear profile plasma. The power coefficient of reflection increases and the absorption coefficient decreases after an early peak with the increase of wavelength in the case that the maximum electron density is greater than 1.0 × 1014 cm-3.