An FDTD model for low and high altitude lightning-generated EM fields
An FDTD model for low and high altitude lightning-generated EM fields
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DOI：
10.1109/tap.2006.874336
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发表时间：
2006-05-01
影响因子：
5.7
通讯作者：
Curnmer, SA
中科院分区：
文献类型：
--
作者：
Hu, WY;Curnmer, SA
为了研究闪电产生的电磁波行为和与闪电有关的电离层现象，建立了一个全波二维圆柱有限差分(FDTD)模型来模拟闪电产生的电磁波在具有高空和长距离能力的电离层中的传播。这种FDTD模型去掉了其他类似模型中的近似，以扩展其适用性，并结合了各种现有的方法和新技术。为了便于实现，该数值模型采用了色散和各向异性的近似完全匹配层(NPML)吸收边界条件。通过修正的折射率法在模型中考虑了地球曲率。采用表面阻抗边界条件来处理任意但均匀的地基参数。通过色散关系对误差进行量化，并对解的收敛进行分析。通过数值模拟、数值波导模理论和实验数据的比较，验证了该模型的有效性，并与其他方法进行了比较。虽然该FDTD模型是为模拟雷电产生的电磁场而开发的，但它也适用于其他甚低频(VLF，3-30 kHz)和极低频(ELF，3-3000 Hz)波的传播问题。
To explore lightning-generated electromagnetic wave behavior and lightning-related ionospheric phenomena, a full-wave two-dimensional cylindrical finite-difference time-domain (FDTD) model was developed to simulate lightning-generated electromagnetic wave propagation in the ionosphere with high altitude and long distance capabilities. This FDTD model removes the approximations made in other,similar models to extend its applicability, and incorporates a variety of existing methods and new techniques. A dispersive and anisotropic realization of the nearly perfectly matched layer (NPML) absorbing boundary condition is adopted in this numerical model for ease of implementation. Earth curvature is included in the model through the modified refractive index method. The surface impedance boundary condition is adopted to treat arbitrary but homogeneous ground parameters. We quantify the errors through dispersion relations, and the solution convergence is analyzed. Comparisons between our simulation, numerical waveguide mode theory, and experimental data validate this model and show its capabilities compared to other methods. Although this FDTD model was developed for the lightning-generated electromagnetic field simulation, it is also applicable for other very low frequency (VLF, 3-30 kHz) and extremely low frequency (ELF, 3-3000 Hz) wave propagation problems.