The return-stroke phase of the cloud-to-ground lightning flash is of primary concern for lightning-protection engineering. This also holds for buried cables and other sensitive devices in the soil. For evaluating the field in the soil, two approaches are employed: first, the quasi-static approach, in which a current source injects the stroke current into the soil; and second, a hybrid approach employing the “engineering model” for the channel-current evolution. In both the approches, the current injected into the soil is independent of the soil resistivity, which needs further scrutiny. The return-stroke model developed by Balaram Raysaha et al. (2011) self-consistently emulates the stroke-current evolution without any such assumptions and is, therefore, very suitable for a comprehensive assessment of the situation. However, the field-computation method employed by Balaram Raysaha et al. had to be changed to the domain-based finite-difference time-domain method for a realistic soil model. After this augmentation, the return-stroke model is employed to investigate the possible role of soil's electrical parameters on the return-stroke current evolution. It is found that for fast-rising currents of low amplitudes, the soil resistivity noticeably influences the current amplitude. Also, it is found that the soil dispersion leads to a significantly lower electric field in the soil.

中文翻译：

---

模拟实际地面上的回程电流演变

云对地闪电的回击阶段是防雷工程的主要关注点。这也适用于土壤中的埋地电缆和其他敏感设备。为了评估土壤中的场，采用了两种方法：第一，准静态方法，其中电流源将冲击电流注入土壤中；其次，采用“工程模型”进行通道电流演化的混合方法。在这两种方法中，注入土壤的电流与土壤电阻率无关，这需要进一步审查。Balaram Raysaha 开发的回程模型等。(2011) 在没有任何此类假设的情况下自我一致地模拟了中风电流的演变，因此非常适合对情况进行综合评估。然而， Balaram Raysaha 采用的场计算方法等。对于真实的土壤模型，必须改为基于域的有限差分时域方法。在这种增强之后，使用回程模型来研究土壤电参数对回程电流演变的可能作用。发现对于低幅值的快速上升电流，土壤电阻率显着影响电流幅值。此外，还发现土壤分散导致土壤中的电场显着降低。