Radio atmospherics (sferics for short) are electromagnetic (EM) pulses discharged by lightning return strokes and can be used for D region remote sensing. A frequency-domain full-wave (FDFW) numerical model is developed to simulate sferics propagation in earth ionosphere waveguide (EIWG). For a certain sampling frequency, EM fields of sferics are decomposed into a series of plane waves in the spectral domain via 2-D spatial Fourier transforms. The magnetized cold plasma medium of ionosphere is divided into several thin layers with the arbitrary anisotropic dielectric constant for each layer. The EM fields at the sferics receiver site are evaluated by recursively computing the reflection and transmission matrices in all layer boundaries for all the plane wave components and performing 2-D numerical integration in the spectral domain. The earth flattening technique is adopted and the horizontal wave vector of each plane wave component is directly modified in the spectral domain to compensate for earth curvature effects. Interactions between plane waves and the magnetized cold plasma of ionosphere are analyzed and discussed. Comparisons between the FDFW computation and finite-difference time-domain simulation as well as field measured sferics are implemented to verify the accuracy and reliability of the proposed new model.

中文翻译：

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中低纬度电离层 D 区无线电大气遥感 I：前向建模和现场测量验证

无线电大气（简称sferics）是由闪电回击释放的电磁（EM）脉冲，可用于D区遥感。开发了一个频域全波 (FDFW) 数值模型来模拟地球电离层波导 (EIWG) 中的 sferics 传播。对于某个采样频率，sferics 的 EM 场通过二维空间傅立叶变换在谱域中分解为一系列平面波。电离层的磁化冷等离子体介质被分成几个薄层，每层具有任意的各向异性介电常数。通过递归计算所有平面波分量的所有层边界中的反射和传输矩阵并在谱域中执行二维数值积分，来评估 sferics 接收器站点的 EM 场。采用地球扁平化技术，在谱域中直接修改每个平面波分量的水平波矢量，以补偿地球曲率效应。分析和讨论了平面波与电离层磁化冷等离子体之间的相互作用。FDFW 计算与有限差分时域模拟以及现场测量的 sferics 之间的比较被实施，以验证所提出的新模型的准确性和可靠性。