本文建立了时变非磁化等离子体平板的一维模型，并采用时域有限差分(FDTD)方法对太赫兹(THz)电磁波在时变等离子体中传播时的反射、透射系数及吸收率进行了计算。然后根据计算结果分析了时变等离子体的上升时间、电子密度、温度以及等离子体平板厚度等参数对不同频段THz波在等离子体中传播特性的影响。分析结果表明： THz波在时变等离子体中传播时，其反射系数受等离子体电子密度和上升时间的影响较大；而吸收率则随着上升时间的减小、电子密度及平板厚度的增加而增大；此外， THz电磁波能够穿透量级为1020 m-3的高密度等离子体层，可以作为再入段飞行器通信以及高密度等离子体诊断的理想工具。%This paper has built the one-dimensional model of the time-varying un-magnetized plasma, and the finite different time domain (FDTD) algorithm is used to calculate the reflection and transmission coefficients, as well as the absorption rate of terahertz (THz) electromagnetic waves in time-varying plasma. The relation between the frequency of the THz wave and the propagation characteristic influenced by rise time, electron density, temperature, and depth of time-varying plasma plate is analyzed. Results demonstrate that the reflection coefficient is mainly influenced by plasma rise time and electron density. The absorption rate increases with decreasing rise time, increasing depth and electron density. Furthermore, the THz electromagnetic wave is an effective tool for the communication of reentry vehicle and high density plasma diagnosis because of its strong penetrability in high density plasma.
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