Ground‐based technological systems, such as power grids, can be affected by geomagnetically induced currents (GIC) during geomagnetic storms and magnetospheric substorms. This motivates the necessity to numerically simulate and, ultimately, forecast GIC. The prerequisite for the GIC modeling in the region of interest is the simulation of the ground geoelectric field (GEF) in the same region. The modeling of the GEF in its turn requires spatiotemporal specification of the source which generates the GEF, as well as an adequate regional model of the Earth’s electrical conductivity. In this paper, we compare results of the GEF (and ground magnetic field) simulations using three different source models. Two models represent the source as a laterally varying sheet current flowing above the Earth. The first model is constructed using the results of a physics‐based 3‐D magnetohydrodynamic (MHD) simulation of near‐Earth space, the second one uses ground‐based magnetometers’ data and the Spherical Elementary Current Systems (SECS) method. The third model is based on a “plane wave” approximation which assumes that the source is locally laterally uniform. Fennoscandia is chosen as a study region and the simulations are performed for the September 7–8, 2017 geomagnetic storm. We conclude that ground magnetic field perturbations are reproduced more accurately using the source constructed via the SECS method compared to the source obtained on the basis of MHD simulation outputs. We also show that the difference between the GEF modeled using laterally nonuniform source and plane wave approximation is substantial in Fennoscandia.

中文翻译：

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空间天气事件引起的地面电磁场建模感应源设置的三种方法比较

在地磁风暴和磁层次风暴期间，诸如电网等基于地面的技术系统可能会受到地磁感应电流（GIC）的影响。这激发了对GIC进行数值模拟并最终进行预测的必要性。在感兴趣区域中进行GIC建模的前提是在同一区域中模拟地面地电场（GEF）。反过来，GEF的建模需要生成GEF的源的时空规范，以及适当的地球电导率区域模型。在本文中，我们使用三种不同的源模型比较了GEF（和地面磁场）仿真的结果。两个模型将源表示为在地球上方流动的横向变化的薄层电流。第一个模型是使用基于物理的近地球空间3D磁流体动力学（MHD）模拟结果构建的，第二个模型则使用基于地面的磁力计的数据和球形基本电流系统（SECS）方法。第三个模型基于“平面波”近似，它假定源在局部横向均匀。选择芬诺斯堪迪亚作为研究区域，并针对2017年9月7日至8日的地磁风暴进行了模拟。我们得出的结论是，与通过MHD模拟输出获得的信号源相比，使用通过SECS方法构造的信号源可以更准确地再现地磁场扰动。我们还表明，在侧面扫描中，使用横向非均匀震源建模的GEF与平面波逼近之间的差异很大。