Abstract

In September 2019, on the Kola Peninsula, an experiment was carried out to generate ULF–ELF signals at night using two decommissioned industrial power lines as a horizontal emitting antenna. The line current was supplied from an external 200 kW generator. The current strength varied from 240 A at low frequencies (0.382 Hz) to 20 A at the highest (194 Hz). The paper presents the results of recording ULF signals at the Staraya Pustyn magnetic station, which is 1610 km from the power line. Signals with frequencies from 0.6 to 6.4 Hz were recorded. The signal amplitudes, normalized to the emitter current, varied in the range of 0.4–0.7 fT/A. For theoretical estimates, two models were used: (1) formulas from the theory of ELF field excitation in the Earth–ionosphere waveguide and (2) a numerical model of the ULF field in the atmosphere and ionosphere created by a linear surface current of infinite length. The numerical model is based on calculation of the system of Maxwell equations in a vertically inhomogeneous atmosphere and ionosphere, the parameters of which are calculated using the IRI model. A fundamental feature of model 2 is that it takes into account the contribution of the ionospheric waveguide propagation to the excited field at large distances at frequencies above the critical waveguide frequency of ~0.5 Hz. The dependence of the amplitude of the recorded signals from an artificial source on a frequency of 2–8 Hz has a nonmonotonic character, which may be a manifestation of the effects of waveguide propagation along the ionosphere.

中文翻译：

---

Fenics-2019实验期间Staraya Pustyn站的Ulf-Elf信号记录和建模

摘要

2019年9月，在科拉半岛进行了一项实验，使用两条退役的工业电力线作为水平发射天线，在晚上生成ULF–ELF信号。线路电流由外部200 kW发电机提供。电流强度从低频（0.382 Hz）的240 A到最高（194 Hz）的20 A不等。本文介绍了在距电力线1610公里的Staraya Pustyn磁力站记录ULF信号的结果。记录频率从0.6到6.4 Hz的信号。根据发射极电流标准化的信号幅度在0.4–0.7 fT / A的范围内变化。对于理论估计，使用了两个模型：（1）来自地球-电离层波导中ELF场激发理论的公式，以及（2）由无限长的线性表面电流在大气和电离层中形成的ULF场的数值模型。数值模型基于在垂直非均匀大气和电离层中麦克斯韦方程组的计算，其参数是使用IRI模型计算的。模型2的基本特征是，在高于临界波导频率约0.5 Hz的频率下，它考虑了电离层波导传播对远距离激发场的影响。来自人工源的记录信号的幅度对2–8 Hz频率的依赖性是非单调的，