Doppler characteristics of EM scattering from sinusoidal or weakly nonlinear choppy waves
Doppler characteristics of EM scattering from sinusoidal or weakly nonlinear choppy waves
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DOI：
10.1080/09205071.2017.1407263
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发表时间：
2018-01
影响因子：
1.3
通讯作者：
Yanmin Zhang;Yunhua Wang;Honglei Zheng;Yue Yu
中科院分区：
文献类型：
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作者：
Yanmin Zhang;Yunhua Wang;Honglei Zheng;Yue Yu
摘要给出了正弦波和弱非线性波的电磁散射场谱。通常，我们认为布拉格共振波的电磁散射的多普勒频移是由水波的相速度决定的。然而，最近的波槽实验和数值模拟表明，当电磁波照射在正弦波或简单的弱非线性波浪上时，不仅可以找到与水波相速度相对应的谱峰，而且可以找到其他等间隔的谐波峰。谐波峰值的强度受水波振幅、频率和水动力模型的影响。为了更好地解释这些现象，利用一阶小斜率近似理论（SSA-I）推导了简单水波谱的理论模型。与数值模拟结果的比较表明，理论谱模型可以很好地解释所有有趣的现象。
Abstract The spectra of electromagnetic (EM) scattering fields from sinusoidal or weakly nonlinear choppy waves are presented. In general, we always consider that the Doppler shift of EM scattering from a Bragg resonant wave is determined by the phase velocity of the water wave. However, the recent wave tank experiments and the numerical simulations demonstrate that not only the spectral peak corresponding to the phase velocity of water wave but also other equally spaced harmonic peaks can be found when a EM wave is illuminated on a sinusoidal or a simple weakly nonlinear choppy wave. The intensities of the harmonic peaks are affected by the amplitude, the frequency, and the hydrodynamic model of the water wave. To better explain these phenomena, a theoretical model for the spectra from the simple water waves are derived by the first-order small slope approximation theory (SSA-I). The comparisons with the numerical simulations illustrated that all the interesting phenomena could be successfully explained the theoretical spectral model.